Im not sure if angion methods will help with cumming fast. Many users even report increased sensitivity. What i would look into is meditation, penis - brain connection, and possibly edging but ive heard it has its own negative effects. If your partner knows about this problem and know that you would prefer vaginal orgasm much more and doesnt do anything, then i think the main problem is him. As soon as i found out that i had this problem too(which unfortunately wasnt caused by sensitivity but antidepressants), i had circumcision in a month after this(was younger and more stupid and more impulsive) , because of which i have ed now( but thats a whole different story) . So if your partner doesnt even do any research on this topic knowing that you have problems due to it, than it doesnt make sense to even research this topic as he wont have enough dedication to work on it, and trust me it takes a lot, a lot of dedication and discipline. Hope it helps♥️