I'm not sure what the shovel adds to the joke. It could easily...

I'm not sure what the shovel adds to the joke. It could easily be replaced by some other item or removed entirely. The human brain likes things in threes, though, so you could replace it with a phone.
Blue paint, red paint, and a phone.
"If she says 'Those are the strangest pair of balls I've ever seen', you use the phone and call your lawyer!"
The point is made, the gag is there, and no hint of violence. (There's still the issue of requiring a woman to be a virgin before marriage, but that's a different can of worms).