Hi Something weird happent to me. Couple of months ago i was with my girl friend and i went down on her then when she wanted to go down i lost my errection. Untill then i have never had a problem i always had rock hard errections. Now since them i got an errection and after 10 minutes it goes down. This usualy happens when i am with a girl. I am planning on taking a blood test this week. What should i tell them to test for? ANy other help is appreciated. By the way i am only 21.