My boyfriend has an issue with the skin around his penis tightening while erect, ihe can not become fully erect anymore as it used to, this also has increased the amount of time before he can perform again. any suggestions or exercises?

See a urologist.: It's not entirely clear from your question what may be happening, but i recommend evaluation by a urologist. If he is uncircumcised, a condition called phimosis where the foreskin does not retract properly could cause this skin tightening and impede erections. An full evaluation will be able to determine if phimosis, or some other dermatologic or infectious cause might be the problem.