hi i am 28 year old.five feet seven inches in height, 70 kg in weight.I am unmarried had sex.with 40 year old lady.my problem is that while during ejaculation The erection does not sustain for a long time with rigidity, and my my penis become small this happens every time during sex. I have four and half inch in length erect penis.sir i have taken my medicine for long erection but it not work..i am able to satisfy my partner.plz give me solution sir what can i do.and i wanted to increase my penis size,,is there any supliment