Green’s Dictionary of Slang

(orig. UK milit.) a euph. for fucking adj. (1)

1959		K. Waterhouse Billy Liar (1962) 137: Will you get your hands off my cowing, sodding, frigging sleeve!
1977		(con. 1940–50s) Nicholson & Smith Spend, Spend, Spend (1978) 18: Cowing bastard, we’ll have them, the cheese and tomatoes, he’s not getting any.