Alright, so there's one thing about this that we can put on the table: Girafarig is possibly the worst fully-evolved Psychic-Type Pokemon excluding Unown and No-Shadow-Tag Wobbuffet. Maybe Lunatone and Solrock slightly edge him out as the bottom of the barrel, but regardless, there's not a lot of victory going on in this echelon.
Let's put that aside for a moment as ask ourselves, "what can we do creatively with Girafarig?"
Well... If you want to be ambitious, you could try a physical Girafarig, it has Sap Sipper, so a read against a grass type attack (with a Pokemon resistant to grass on your team so people think you might swap into that) will give you an attack boost. It definitely has the stab to do so, it has Return for physical stab at 102 damage, and Psychic Fangs at 85 power. It's other abilities in terms of usage aren't that good, unless you want to stop flinching, or wake up faster (which Spore is commonly used as a sleep-inducing move anyway, so Sap Sipper is better).
... Otherwise, we can have this moveset, which I think might work out:
The most important thing for Girafarig is some sort of defense, in which comes in the form of Light Screen/Reflect, to make advantage of it only having two weaknesses, Dark and Bug (This is why I did Light Screen/Reflect, . It depends on whether you want to take physical or special attacks better for the rest of your team, and will be set up fast, since Girafarig has a decent speed stat. To make up for the screen, give it either a Kee Berry, or a Maranga Berry depending on whether you have Light Screen or Reflect. If you have Light Screen, use a Kee Berry, so that people are forced to use a physical attack on you to do more damage. You can have Psychic/Psychic Fangs/Return/Hyper Voice for stab, the variety is there depending on whether you'd like an physically, or specially offensive Girafarig, Wish, to heal, of course, and either Toxic/Baton Pass/Recycle. If you want to continue a chain of berry defense boosts, then go for Recycle. Choosing Toxic can make the Girafarig a mini staller, and can be used as a distraction, since it can set up walls, and have enough defense to land Toxic and Wishes. Finally, if you choose to do Baton Pass, you can not only Baton Pass a Wish, but also a Defense boost, an attack boost, and a screen if you set it up.
Overall, I suggest that the nature is Timid or Jolly, depending if you want to run either physical or special Psychic or Normal stab, otherwise, I'd say invest the stats in an attack/special attack reducing nature, and increase the defense/special defense stat depending on what you want to protect against most. The EVs, definitely required in Speed, to set up a screen, Toxic, Recycle, or Baton Pass, it requires quite a bit of speed, hence why I suggested a Timid/Jolly Nature. Otherwise... I'd say for the remaining EVs to put them equally into each defense stat, and the last four EVs into special or physical attack. Though, 100% with an ability, put Sap Sipper, it's a free resistance to Grass type, and allows you an attack boost, in which can benefit you if you put some physical investment in it.
Naturally, I want to give a Girafarig user a choice, hence why the movesets I suggested were a bit bland, but it should work, it gives it some defense to Girafarig, and is a bit different from the Nasty Plot ones you see every so often (which is the easy way out when making a Girafarig set, then give it a Focus Sash/Weakness Policy or something). Hopefully this is interesting to whoever looks into it, but this is my vision on it, I could make something tonnes more interesting, but I'm a little tired at the moment, I'm gonna get back into competitive Pokemon fully once Sword and Shield come out.
Hmm, Support Girafarig. I think that's what GameFreak wanted, (assuming they even have a play style goal when they design specific Pokemon), with Baton Pass. I've always kinda hated Baton Pass as a concept: making a Pokemon designed just to pass a buttload of boosts to an ally? Kinda lame tbh, but it could still work pretty nicely if it wasn't banned in Showdown. Sadness.
I feel like you need to do something really unexpected with Girafarig to make it happen. I was playing around with Z-Skill Swap with an ally Quagsire: Bate the Grass attacks, then try to steal a better ability once I've already gotten the boost from Sap Sipper. It has the added bonus of boosting your speed 1 stage, which Girafarig kinda needs to outrun a lot of stuff, but then you have the question "Is it worth your Z move?" Probably not. I was trying to run a Physical set with the moves
But Work Up just isn't enough to KO things. You'd go farther with Nasty Plot, Psychic, and Thunder/Thunderbolt, but I'm just not sure how far the Skill Swap will go. Maybe I'll experiment with a Weakness Policy set with Agility. I can sacrifice speed EVs if Agility gets used, which I can pump into defense to tank a Knock Off better.
As for Skill Swap, I did notice you could pair Girafarig up with Mega Swampert then Skill Swap Sap Sipper onto him in doubles. The only other Pokemon who can do that is Stantler.
That's quite a smart moveset actually, considering you get rid of the grass weakness of a fellow water/ground Pokemon, perhaps then you can (if you have Nasty Plot on your set) carry Energy Ball to increase the attack of your either Quagsire or Swampert. You can take advantage of Swift Swim too. You could try give Swampert/Seismitoad Rain Dance, so then you won't need Agility, and instead Girafarig gets a speed boost for Swift Swim. Afterwards, then you can continue with starting off with that Physical set, by getting a Work Up first turn after the Skill Swap. Afterwards, you get a Swift Swim sweeper Girafarig. Possibly after that, you can make either Seismitoad/Swampert a support, by making them tanks, and giving them Sap Sipper with Waterfall.
As with the Baton Pass set, that was just an option, you can also veer into a Toxic set if you want a staller, or Recycle if you're confident Girafarig will live a lot of hits.
Girafarig's 70/65/65 bulk is not really winning any awards for longevity without sweeping. I'm really sad they didn't replace Early Bird with Simple back in Gen IV, to be honest. Nothing about Girafarig has anything to do with waking up early, meanwhile Simple could've represented both of Girafarig's heads being affected by stat modifiers. Simple Girafarig would probably still be fairly weak, PU at best since he'd face competition with Swoobat who's pretty likely to get off that initial Calm Mind and has access to Stored Power, but would probably be a bit better to play around with. There is something to be said about Simple Nasty Plot, though. Maybe with Salac Berry, you could get in some epic sweeps? But the low bulk would make that a gamble.
Been playing around with a more sweeper esque set with Weakness Policy
- Psychic Fangs
The trick is actually taking a Knock Off or U-Turn at full health. The 1.5 boost from Sap Sipper just isn't enough to OHKO a lot of grass types, and their's a fair chance the opponent won't even bother to try and swap for a mon carrying Dark/Bug, so I don't even get the Weakness Policy to activate before taking neutral damage, and from there, it's not happening. You can only survive if you're at max HP.
The thing is with that set though, it's quite difficult to get a free speed boost, considering Girafarig wastes a turn when it uses Agility. (and most of its HP if someone attacks it due to its fragility) Naturally, Girafarig would need a speed boost, and an attack boost to sweep, but I'm not sure how you would be able to give it an attack/speed boost safely without sacrificing too much HP. I'll look into it later.
Very true on that part. My suggestion for healing moves would be Wish, it seems to be the only healing move it gets (that's actually quite good). It can be used instead of Agility if you need to heal for the next turn, and are confident you can knock out something the turn after if someone decides to swap from Sap Sipper.