Edge 10 times.
[Pain] Put a clothespin on each of your nipples before edging and remove them once you are done. If you pull them off by force without opening them, you may reduce your chastity by 3 days. The clothespins cannot stay more than 25 minutes on your nipples. If you fail to edge 10 times by then, then remove them without opening them. In this case you obviously won't get a chastity reduction for this.