It can vary- it will take less time than it would with sex, generally, as you can do exactly what you like and what feels good for you. I would say that between about 5 and 10 minutes would be an average, but you can make it last longer if you want. If you wanted to slow yourself down then try 'edging'. Get yourself to the point where you are about to come, and then stop for a minute and then continue slowly when the feeling has passed. Repeat this and you will be able to hold back your orgasm until you are ready, as well as (some people experience this) having a stronger orgasm when you allow yourself to reach that point.
when u feel like ur about to cum slow down so u can last longer then speed bak up when ur ready
but i come little to early .. any suggestions ?
ummm 20 minutes? haha
3 hours, minimum!