Sphincter pain when coughing

Medicine: sphincter relaxing

Good day my friend and I (homosexual couple) would like to have anal sex but he gets pain every time I come with my penis against his inner sphincter we have already tried a spray that is supposed to numb the anal area but without success and now I wanted to ask if someone had one Possibility knows how sex can work more comfortably and without pain for my partner? The main problem here is with his internal sphincter muscle because it does not open.

We have already tried plugs, but as soon as there is tension on his sphincter muscle he starts to hurt

and therefore I don't want to hurt him or hurt him, we are looking for a solution to our problem

if someone has a tip or helpful information for us, we would be happy to hear from you

Sincerely

Dominik and André