Vampire-comedy movie ID

I remember a comedy about vampires… maybe from the late 1970s or early 1980s? The young non-vampire protagonist was a virgin, which was important for some reason. As the vampires were closing in, his girlfriend had sex with him (in a coffin, IIRC - how’s that for kinky?) and then triumphantly announced to the disappointed vampires that he wasn’t a virgin anymore.

What movie was that?

Once Bitten, with a young Jim Carrey as the lead and Lauren Hutton as the vamp after his virgin blood.

That’s it - thanks! I didn’t remember the lead being Jim Carrey.