Just from the question alone my first thought was this...<br />
Must not last that long.... <br />
So can we get an average time here to figure this out? I am sure you must be proud considering the question so surely you would share that openly as well.
Need to build some stamina not even sure if that is possible. However I would suggest to looking into ways to last longer your self.
Sorry to say but that reminds me of the half minute man joke.
I have to agree with lost on this. I think 30 should be a minimal to be honest.