Chances are if you have inhibited, also referred to as delayed ejaculation (DE), you and your partner are very frustrated. Contrary to what you may initially think, you do not need more stimulation. After ruling out medical and pharmacological factors, a good look at your life and relationships would most likely help you identify causes.
Are there times when you do not experience DE? For example, in regular life you have DE, but not on vacation. Or, perhaps you have DE when angry with your partner, but not other times. Perhaps you have learned an idiosyncratic way to masturbate and can only ejaculate with that type of stimulation. Sometimes that method may be stimulation to porn. Other times it may be extremely vigorous stimulation.
Most likely there are circumstances that contribute to your DE.
A certified sex therapist can help you identify causes, then help make a treatment plan for you.