The Beauty was the Beast

Siggi Selector is a pick up artist who approaches a super hot beauty in a club and starts an indirect conversation. He masters sticking points and dates Isabel at the beach on the next day.
Siggi starts a roll play game and it turns to an erotic play in the water. The same day they go to bed together but then something shocking happens. Siggi has never experianced an adventure like this in his life before, and never again later.
What did Siggi learn from this?