What is a "second puberty"?

Monica
Question: Lately I have been finding myself more horny than usual. Granted I'm not sure if it's due to the fact that I'm not on BC, or that I'm getting older (29 this month), or I'm just mentally in a good space with my BF at the moment. And typically I have an extremely low sex drive, like once a week if that. But I heard someone throw out the term second puberty and I wasn't sure what that was exactly or what it consists of bc the person who said it didn't know either... I've also been having different fantasies lately, but I'll address those in another post. Is this "second puberty" the reason why I've been feeling so frisky lately?