death grip don't allow me to have a good sex life

I can have sex, I can have a long erection but I can't cum. My gf doesn't want to have sex yet but besides that in sex we do any kind of things but I can cum without fap myself.
I watch a huge amount of porn. I don't think is only in my mind problem but more like a physical problem.
Do you guys think I have the death grip syndrome? How many days I should avoid masturbation? Can I have bj and this kind of thing meanwhile?