I like fucking!
Shagging
Movin’ the Hamper.
At least, that’s what we call it, since we have to move the hamper to block the door (which doesn’t latch) to prevent the cats from coming in and nestling down on the bed (as is their habit). Beasts with four legs and the beast with two backs don’t mix (though, uh, YMMV).
Rogering
or
Porking
or
Getting your rocks off
Hey another one, Olde Englishe terminology
SWIVING…honestly, look it up
I’m fond of an archaic term, though I don’t use it much:
dippin’ the wick.
From candle making, y’know, where the wick is thrust repeatedly into a pool of molten tallow until it swells and grows large enough …
makin’ bacon
makin’ whoopie
I suppose it depends on what you are using the term for.
I like “bouncy bouncy bouncy squirt” myself. But its a little cute.
I haven’t seen anyone mention “scromping” yet. Great word.
There’s a brit term I kinda like: rumpy-bumpy.
Ooooh, I know!
The full term is “discussing Ugandan relations.” It stemmed from an incident in the '60’s when a Ugandan foriegn attache was caught in a compromising position with his mistress in, of all places, a bathroom at Heathrow airport. The fine British satirical magazine Private Eye found the affair amusing, and, for several months afterwards, referred to any such sorts of activities as “discussing Ugandan relations.”
For the record, my preferred term is “we got (or were) busy,” as in the line from Digital Underground’s masterwork “The Humpty Dance”: “I once got busy in a f**kin’ bathroom.” Hey, maybe DU got their inspiration from the same incident!
Not Old English; more late Middle. In any case, fucking, boinking, rogering, tuning the old banjo, hiding the sausage, whatever.
Interesting thread.
- PW
PALEWRITER: Well middle ages is kinda old innit?
…and what about Goosing,Having it away,Greasing the pole…oh I could go on but I’m gonna have a shag in a minute, I’ll be back in 90 secs, I’m a stayer y’know 
You know National Lampoon is written from a male perspective when they come up with “drivin’ the ol’ skin bus into Tuna Town” but I’ll go with plain “copulating” on this one.
Copulate With Extreme Prejudice
Twist the Sheets
Tickle the Ivories
Mate
Breeding Dry Run
Workout
Ooh, oh, uhhh, yeah!
On a seperate note, I’ve heard old guys, after downing a shot of whiskey, say “something for my wife’s kidneys”…
floggin’ the dolphin
choken’ the chicken
I guess you can tell I am single.
copulation
monkey bizness 
ccwaterback Stop floggin that dolphin!! (unless it’s concentual 
)
jiggy jiggy
Me and an ex-gf once listened to a radio show with some woman preaching abstinence until marriage. According to her, the trick for young lovers wanting to stay virgins was keeping your mind off sex and making out by finding other activities that both enjoyed. The one example she gave was ‘going to the library’.
We went to the library a lot after that…