I wish perfume covered up the stench of being unclean, a la 18th century France. Right now, it changes your scent, but you can't use it as a way to block out the scent messages that come from sex or just not washing for a long time.
But perfume also does not completely cover up your stink. In game, or in real life. Especially not in real life. If you want to not smell like ass, bathe.