My penis erection period is too short i want to make it long so what to do?

Find the reason: Without knowing the cause for it, it is much harder to treat than if the cause was evident. More history might help better with this. Pills like viagra, cialis, levitra, (vardenafil) and like seem to provide fairly good results with achieving and maintaining erection, although, don't be lured by it w/out pursuing search for the underlying cause.

Depends: You need to be more specific, if you ejaculate as soon as you penetrate and your penis looses the erection, you may fit the diagnosis of premature ejaculation. Sexual therapy, Lidocaine cream and some anti depressants may work.