If you want to nep a Nep Nep, first you need to obtain a Nep Nep.

This Nep Nep on the left looks good. Perfectly neppable.

This Nep Nep on the right is not neppable. In fact, it isn't even a real Nep Nep. Notice it only has one plus accessory in her hair. This is Nepgear. Nepgear isn't Neptune. Neptune is Nep Nep. Get Neptune. Not Nepgear.

See Nep Nep up there? Nep it.

I dunno, I guess just push buttons and stuff until you're satisfied with how much you've nepped.

This is Histy. She will teach you more if you ask her to. Don't ask her stupid questions though, she might get Pissty.