I just MO in the shower to my memories (my gf giving me a handjob and the ass of this girl I saw at the mall a week ago). It took me like 1 minute to cum and I was only like 50% hard. What doesn't make sense to me is I was able to get rock hard with my girlfriend the last two times (first time we just edged, second time I came in her mouth). I've been frequently getting morning wood and much harder recently. I decided to MO today to help build stamina but I ended up cumming in 1 minute and while being 50% hard. I don't know what I did wrong or what is wrong other than PIED problems. Help please