Yes, yes, yes!
The best for me is the actual bath tub faucet. I just lay down in the tub and prop my legs up along the sides and think dirty thoughts. lol
It works in a pool as well. lol :X
As for shower heads, I've never found one that works for me, but I bet I could if I tried.
and ladies, just so you know, masturbating in this fashion all the time CAN give you a yeast infection. It's like douching for several minutes (however long it takes you to come) and CAN cause irritation leading to yeast infection.