1949 E. Partridge (ed. 3) Add. 995/2 Boffing, masturbation.
1977 (Nexis) 4 Sept. g1 Much talk of ‘boffing’.
1990 J. Updike ii. 257 Dad, when are you going to get your mind off boffing?
1997 D. Hansen xiv. 164 Take her out and give her a darn good boffing. That'll do the trick.