Helping a mate out

[rebbonk]

I was in the pub with my mate last night when he said to me, "Look, mate, I've been having an affair and my wife's getting suspicious. If she asks, I was with you last night."

I nodded. "No problem."

A minute later, his wife came into the pub and said straight at me. "Dave wasn't home last night - I think he was sh*gging some sl*g!"

"No, he wasn't," I replied immediately, winking at him.

Spoiler:

"He was sh*gging me."