From English - German Ding/FreeDict dictionary ver. 1.9-fd1:
boffing /bˈɒfɪŋ/
fickend, vögelnd, bumsend, poppend, pimpernd, rammelnd, pudernd
Synonyms: fucking, banging, humping, screwing, poking, mashing, tumbling, shafting, knobing, shaging, rogering, bonking, boinking, boning, shtuping, schtuping, rooting
see: fuck, bang, hump, screw, poke, mash, tumble, boff, shaft, knob, shag, roger, bonk, boink, bone, shtup, schtup, root sb., fucked, banged, humped, screwed, poked, mashed, tumbled, boffed, shafted, knobbed, shagged, rogered, bonked, boinked, boned, shtupped, schtupped, rooted