When I played rugby, the med kit had a whole bag of special nose-tampons (basically tampons, minus the string, but actually designed for bloody noses) for shoving into your nostrils before going back into the game. (If you bleed on the field, they'll kick you off). The pain of jamming one into a bloodied-and-possibly-broken nose was exquisite, but at least they stopped up the flow for a while.

(Also, flashing someone a thumbs up while black-eyed and double-nostril-nose-tamponed makes for either an awesome photo or excellent blackmail.)