"I suppose it's funny to talk about...But it's not funny when it happens to you," is a news quote that applies to nearly every sex story. In this case, however, it talks about Priapism, that surgeon's general warning on Viagra about the perils of a 4-hour erection. The good news is that the doctors interviewed have never had a patient actually come in with an engorged cock due to erectile drugs, but the problem can be caused by a number of other physical problems, and could cause penis damage. So, stop worrying, pill-popping grandpa penis: an excessive erection is the least of the problems Viagara can cause for you - it's just the funniest one.