I always have unprotected sex w/ my partner. the last time we had sex there was this weird smell. i took a bath and the smell was gone..what was it?

Fishy odor?: If the smell was of a fishy nature, it was likely due to Gardnerella bacteria.

Bacterial Vaginosis?: A bad smell after intercourse is sometimes a sign of Bacterial vaginosis. This isn't technically and infection but an overgrowth of some odor producing bacteria. When you have intercourse, the bacterial release amines that have a strong odor. If it happens just once, I wouldn't worry about it but if you have a discharge or if the odor happens again, you should get an exam and treatment.