I am now 48yrs; since I was at least 18yrs when placed in a 4F's situation, my anxiety creeps in to such an extent that I am unable to perform sexually. What I have found is that when my potential partner is relaxed with and interacts, I am perfectly okay and am able to have sexual intimacy; however when a mechanical response is required, it generally kills my entire system and I would require to take a male performance stimulant in order to have sex, otherwise I choose not to engage.
This behavioral response for me has left me embarrassed at times, however I understand and generally need to explain to potential partner not to be mechanical, following which I am able to perform.
Is there something that I can do to overcome this and go into the 4F's mode.

Thank you