They tend to get the most laughs when used as a zinger. In general, dick jokes tend to be funnier when short and sweet. For your buds at the bar? Probably the safest bet. For your mother-in-law? No, but then again, I don’t know the relationship you have with her. Are dick jokes for your co-workers? Absolutely not. The key to telling a dick joke is knowing your audience.
The common factor among all of them? Penises are pretty funny. There are jokes about big dicks, small dicks, and not having a dick at all. Dick jokes, very much like actual penises, vary greatly, coming in all shapes and sizes. Ah, the dick joke-a staple among comedians and laypeople alike.