Do you have to pull your foreskin back when you have an erection? Why don't you just leave it forward?
It sounds a though you may have what is called "frenulum breve" which simply is a short frenulum that limits retraction of the foreskin. If that is the case, a urologist can do a minor operation to relieve this constraint on retraction.
You are blessed with an erogenous, highly-innervated, protective foreskin. Many unforeskinned guys would envy your foreskin even though it does not retract. You display great wisdom in wanting to avoid circumcision.
You are very fortunate to have parents that did not circumcise you. You have a whole, complete penis so you have sex the way nature intended it.
That piece of skin at the bottom of the glans that connects the foreskin to the head is called the frenulum. Almost every male is born with a frenulum. It is normal and it is supposed to be there. The frenulum has a high level of sensation because of its high innervation and serves to limit the rearward travel of the foreskin. The stretching of the frenulum during sexual intercourse helps to trigger ejaculation. Pulling the foreskin back with too much force can tear the frenulum.
If your foreskin bunches up behind the head when you retract you most likely have a short frenulum (frenulum breve). Test it by pulling back on the foreskin. If the head of your penis bends down when you pull back your foreskin, you have frenulum breve.
You can have sex as you are. Just use lots of lubrication and penetrate slowly, gently, and carefully.
You can stretch the frenulum manually just like you do your foreskin. The stretching is slow because it only goes as fast as tissue expansion That is the best course of action if the frenulum is too short to permit your foreskin to retract. Search the Internet for:
“How to Fix Phimosis and Tight Foreskins, Solutions That Work”
and you will find the information you need.
There also is a minor operation to relieve the frenulum, called frenuloplasty and another called frenectomy. One of these might be necessary, if the stretching does not work. Urologists do this.
Don’t let anyone sell you a circumcision. Circumcision is NOT necessary to treat this condition and is very harmful.