Just say "I have endometriosis and today it's causing me some pain". If he wants to know more, he'll ask. If you aren't serious with him yet, don't tell him too much, just the basics. No sense telling someone everything about your endo if it's going to be a short term thing :) Just think of it this way, every time you tell someone (male or female) about your endometriosis you are spreading knowledge and awareness, and that's a wonderful thing.

Hi doll,

I'm a very open and honest person, even if I am just having some fun with someone, I tend to let them know what is going on. And nearly every time they have been so understanding. Weather it's that it hurts or that I NEED to use a Condom ( which most guys don't like 🙄) if you give them enough info then they get it xx

I agree with Resa. There is no need to hide or omit that we have Endo. I say I have endometriosis and most of the time I find they are either curious or are like okay cool let me know if I can help. Never had a bad experience sharing with anyone. From complete strangers to people I've know for years.