[shameland]

If you want to make your sub earn their orgasms, then once a week, you set them a middle school-level homework task. The task should be some kind of boring essay or a bunch of math problems or something similar that they won't enjoy at all, but is still fairly easy and shouldn't take longer than an hour or two. When they hand the homework in, you grade it: A, B, C, or F.
A grades get the sub a full orgasm.
B grades get the sub a ruined orgasm.
C grades get the sub no orgasm this week.
F grades get the sub no orgasm this week, plus they have to write lines before you give them another homework.

Obviously, this scheme works best in ageplay situations, particuarly if your sub ageplays as a 10-14 year old. Or if not, you could just be degrading a regular non-ageplay sub by treating them like a child.
If you make your subs handwrite their homework, you could also give a failing grade to work that isn't written neatly enough, and make them do it again along with their lines.