never been able to ....you know...finish?

hi everyone. i’m posting this anonymously because i know i would be mortified if someone like my mom found this. anyways . i’ve been masturbating pretty regularly for a couple or years now. (think every 2-3 ish days) and not once have I ever been able to finish. i just can’t seem to get myself all the way there. i’ve tried everything I can think of but once I can tell i’m getting close I just stop, and can’t do it any more. What am I doing wrong ?