<s>[INST] Hi, I'm a 23 year old lad and have a couple of questions re: sexual health: A while ago....whenever I masturbate I would always cum- a fairly heavy load etc.and it would always feel great. Now when I masturbate - everything seems and feels ok except I've noticed that the orgasm doesn't last for as long and when I cum there appears to be less semen...is this normal? I am worried about my testicles. Also, sometimes I can stay hard and go for hours and other times I can't last for more than 10-15mins?....again is this normal? [/INST] Hi, It can be due to thyroid imbalance and testosterone deficiency. Kindly test for hormonal problems. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. S. R. Raveendran, Sexologist </s>