When I lived in Egypt, rinsing with cold water was EASY, because the shower head was on a hose.  I just took it down and turned off the hot water.  Lean over real far, no problem!  Since we had to come back to Texas (It's a long story, guys, and most of it was not pretty.) rinsing in cold is more difficult.  I tried it once, kneeling in the tub and sticking my head under the faucet.  But I tell you, it works!