I dont know anywhere else to ask for advice so i hope its okay here

I have been on T for around 4yrs now and have had a decent amount of growth. I hoped that with that growth would come more sexual pleasure but i cant seem to finish. I feel guilty that my gf cant make me finish and she has been so patient with me always willing to try new things. But even when i mastrubate it takes so much effort, i have to tense up my legs and be in a specific position and have to be watching porn with nobody else in the room. I feel ashamed and disappointed in myself and i just want to feel the close connection you get with a partner after an orgasm.

We have tried having her out of the room while i watch porn and mastrubate till im close or watching porn together ect.. but i can see how it makes her sad i dont want her to feel like she is the problem because she isn’t. It is so frustrating and i dont know why this is happening. Is it in my head? Am i the issue. I want to try the HotRod i hear its amazing but im scared it wont work and that it will just disappoint me and make me feel even worse.

Does anyone have tips. Why is this happening to me?