We call it fucking…or, more precisely, we say “Wanna wanna wannafuck?”
-Tcat
“rumpy-pumpy”
[sup]Well not me personally, but I have heard it used[/sup]
Shagging
Makin’ Whoopie
Tearing one off
“DO ME!”
Well, I only use sign language to describe it… 
Much more fun that way.
Givin’ her a pickle tickle.
Scroggin’.
Horizontal bop.
beating up her guts
Making a deposit at the bank.
Putting the baby batter in the oven.
Joe Bob Briggs had a lot of Shakespeare-inspired eupemisms.
“They were making the Sign of the Two- Backed Whale.”
“They were making the Sign of the Double-Gilled Anaconda.”
His best, however, was the simple yet elegant
“She was pointing her toes at the moon.”
I just heard Boingy Boingy…
Don’t forget “the 14-letter “S”-word”
(Snugglebunnies!)
SNUGGLEBUNNIES!
SNUGGLEBUNNIES!
SNU----
Censorship!
Getting Frisky
Humping
Pushin’ dirt.
Only applies if you’re up the wrong 'un
I call it “being bitter because everyone else my age is having it and I’m not.”
My wife gave me a look of disdain when I asked if I could “knock the bottom out of it” once
Thanks to Futurama, I can now refer to the act as “playing pelvic pinochle.”
My favorite phrase comes from an Onion article: “good old-fashioned frottage.”
But I’ve always been a fan of the aforementined “horizontal mambo,” myself.
The wifey and I call it “Snu-snu”, another Futurama reference.
PORKING