"Chris and Julia were stunned when Barnabas revealed that he'd learned in the past that Chris' curse came about because, beginning with his great-grandfather, there was no way for the men in Chris' family to keep it in their pants for very long!!"
No need to feel like an idiot. There are so many plot points in 1225 eps that it's impossible to remember them all - especially if you haven't watched certain storylines in a while. And actually, rediscovering things you've forgotten is one of the fun things about rewatching the show.