I was 19 and flatting in a mixed flat for the first time. A female flatmate and I became quite close and one night she got into my bed, fully clothed. Being quite naive about women, I thought nothing of it until a couple of days later, mid afternoon she came into my room, locked the door and slipped off her blouse. She had magnificent full breasts, and she made it clear that I was wanted in bed, removing my clothes and pulling me into bed. We were both virgins but instinct took over; I recall she smelt divine. I was so worried I was hurting her; I could feel her hymen resisting me and then give way but she didn't give any indication of pain. It actually wasn't that great and there was a fair amount of blood; when they saw the sheets my male flatmates congratulated me on my "conquest" as they put it, little did they know it was their flatmate.
She was back next day and things got much better throughout the next two weeks, I worked out how to make her cum before me and in one of these sessions she "wet" the sheets. It happened again occasionally and she was mortified each time it happened, it didn't worry me at all.
We soon made an appointment at the sexual health clinic so we could stop using condoms and during the appointment she mentioned to the nurse about wetting the sheets during sex. Nurse asked a few questions and then congratulated her on her squirting achievements; neither of us knew it was a thing before then. We used a towel on the bed from then as we were both keen to find out more and it became a regular thing.