Green’s Dictionary of Slang

a euph. for fuck v. in various senses; also as n.

1902		Boston Globe Sun. Mag. 21 Dec. 7–8: After the junior promenade a student is said to be ‘frapped’ if he has been staying up nights to attend the festivities.
1904		Sydney Sportsman (Surry Hills, NSW) 27 Apr. 3/6: Some fatuous, fathead fish-frapper writes to‘ 'John Norton. Esq’.
1992		Eble Campus Sl. Fall 3: What the frap is going on?