I have asked this before but noone seems to remember this book. It opens with a husband and wife in bed. He is about to go to prison, she is cold towards him. When she is asleep he tries to move her into a position for love making but she awakes, tells him not to be so stupid, and goes back to sleep. Sounds naff but it was a really hilarious book (no other sex scenes in it). I read it 40 odd years ago and would like to read it again. Unfortunately I borrowed it from the library and it really was a random choice but I believe the author's name started with a 'w'.
Would anything by Donald E. Westlake fit the bill? He began his writing career in the 60s and is famous for his "comic capers." Can't help you much more, though, but will keep looking.