Minimum one or two hour of PM before O, that's a lot of Dopamine being used in your brain. Dopamine is a pleasure chemical being released when you feel
pleasure. Orgasm is said to have the strongest Dopamine release, similiar to how heroin users feel when they get a Heroin High.
Dopamine while using PM is artificial while Dopamine during intercourse is natural. That's why we should ejaculate only during sex.
Death Grip is basically how you hold your penis during PM. This affects your penis, erections and orgasms and now when you have sex with a girl, you suddenly can't have erections with a girl, that's a result of Death Grip and PIED (Porn Induced Erectile Dysfunction).
Hope this helps?