I am currently 20M. So since I was young, whenever I've wanted to pleasure myself I've done what's known as prone masturbation, where i lie face forward and continuously press my penis down. While doing this I would often also not become erect. Around a normal age, 10/11 I started to also *** doing this, while still not being erect. I believe this may be a bit more common for younger children when they first start to know what their body parts do, however I didn't stop doing this, and continued to do it as my main way of pleasuring myself all throughout my teenage years. Therefore, I lack experience on pulling my foreskin back, and I find the area beneath my foreskin sensitive to touch. I have been in a relationship with a girl for just over a year now, and at first due to lack of experience I had sexual troubles, initially with fitting it in but now the issue is I have been unable to finish off the job. I also have anxieties while doing it to the point where I try to make sure my foreskin doesn't pull back while I do it as it would be sensitive and hurt otherwise. My girlfriend has been really good about it and tries to gently encourage me but I struggle, and I can sometimes seem avoidant to sexual activities because of anxiety surrounding this, even though I just want to have a normal sex life like the majority of other people. I'm not sure whether I will need to see a doctor or anything or if there's anything I should try, or if prone masturbation for too long has messed me up(I might add that I have stopped doing this for the past 7 months now). I also do sometimes struggle with keeping elections, although I do take viagra on occasion which does help. We do enjoy having sex, it just gets annoying because I dont ever ***. Really appreciate any responses to this.