I offer a-levels at discretion, because I don't want every man who walks through my door to expect it, they could be far too large for me, too rough or I may just not fancy it at that time! I don't charge extra for it at all, but I do say it would only be available on bookings for an hour or longer (because I prefer an enema before anal sex, this means more time for me to prepare for the booking, it just wouldn't be worth it on a half hour).