My Wifes Cousin Sat Down in my Lap

I was with my wife at a family get together of her extended family. About 20 of us were in a large room sitting around talking when a 17 year old girl, my wife’s 2nd cousin, came in and started flirting with me. Long story short, she came and sat down in my lap “because there are no chairs left”. I looked at her and said “I hope you can find a shovel”. She said “Why?” to which I replied “So you can dig a hole big enough to bury me if my wife comes in and sees you sitting in my lap.”