Hello, right on the topic of 18 years old, I'm a virgin, so I've been masturbating for a long time, but I've noticed that when the penis "stiffens" it can't stay that way for a while, I have to be very aroused to last longer. I want to ask you, is this normal, can I get tired of masturbating, will it be different with a WOMAN I hope this time my topic will be published, as it is quite important to me!