Catch and Keep — Hannah Bernard

Jake Benford quickly discovers that being best friends with an eccentric genius can be trouble when Sarah Hamilton turns him into her very own guinea pig. Especially when she's researching human sexuality! And what's even more confusing is that he's starting to like it far too much! But after a few arousing experiments, Jake can't fight it anymore. Now that she's caught him, he might just want to keep her for good.