Whenever Jughead wants a burger, Archie is there to put his meat between Jughead's buns.
I mean, he fucks Jughead. In the ass. Just to be clear. Archie puts his erect penis into Jughead's anus. I'm not good at making sex euphemisms.
A scene of Fred and Shaggy having a gay threesome with a costumed villain raises... erm... raises a question. Is it appropriate to yell 'Zoiks!' when you can't hold it any more and cum misses your friend's mouth?
There's also a joke about putting rubbers on when fucking in here somewhere.