How to hold for longer while on bed?

hello all, no vulgar answers please...

I have heard of certain people can hold even more then 30 minutes while on bed, i know some supplements or some medicines (pills etc) can hold your muscles tight for loner duration i.e. 30 - 45 minutes but i dont like to take such elements because they are unnatural.

May be little silly but when i see ****, i see those males can hold off even more then 45 minutes sometimes.. so hows that possible? Is there any trick involved or its always a steroid or some medicine that helps?

By the way i am a male & want to have a power to hold off on bed for at least 30 mins... i could only hold off for 40 mins only once in my life time till now. I am married & its 4 years of my marriage...

I am very open & curious though to know new ways & try them... but holding off for longer time i tried a lot but couldnt success... Can the members on yahoo answers comment over please?