Quick Definition: When a girl (or guy) cries during or after sex, it is usually after an orgasm although it can happen beforehand.
Women can explain this better than I can. Sometimes, guys cry too. If you can meet someone who you feel trusting enough to reveal your whole self, the result can be very gratifying and scaring. You are emotionally vulnerable. Women feel these emotions in more depth than men, and therefore tear-gasms are more likely in women than men.
However, any type of crying from being vulnerable is generally a beautiful thing and deserves the love and protection of his or her partner.
If a girl has a tear-gasm with you during sex, try to hold her and ask her if she wants to talk. Depending on the girl, sometimes she just wants to be held. Other times, she just had a very emotional and spiritual experience with you, so protect it, and don’t judge. Tear-gasm is parodied in the media because the idea is so funny and strange, but remember that in reality it means that you just got a glimpse into the girls’ vulnerability and with that power you should be responsible as a gentleman.
The girls of TMI explaining why they become vulnerable during sex:
Usage: A tear-gasm is a great experience if you can understand it.