maybe I should have added that I'm female, and that I'm the sub this time?

I can even tell you the concrete reason why I posted my question now, it was because I was kind of freaked of an order from Sir and wanted some kind of answer that proved some of the things (mainy the time limitations) wrong that I had read on the net (thanks to curtis I could gather enough courage, and it did work for more than those 30 mins. without problems)