Originally Posted by Ustwo

For you yes.

You are still pretty much a child. You claim to be 18 (I use claim because I wouldn't be shocked if you are younger), you have an anime avatar (yes I think that says something about you), you are worried you are not able to work out enough to bulk up, and you are into porn.

I'm going to go out on a limb and say you are also a virgin, or at best very limited and fumbling experiences with females. This is not to be condescending, this it to be factual.

The problem with constantly jerking it, is it becomes a demotivator. The desire for sex is a great motivator. At your age, I felt under muscled as well, had limited confidence, and probably would have felt an anime sig was cool provided anyone payed much attention to anime then, or that there was an internet beyond Gopher and university systems.

Masturbation would just be a demotivator for me, by taking off the edge you take off a lot of your drive too. Rather than fapping, letting that sexual frustration build up a bit will give you the energy to push yourself over the top in your work outs, to get the guts to approach that really hot girl, to in short be a winner.

Do this and you will find that soon you will have far less need to masturbate, mostly because she will do that sort of thing for you.