If I were a priest, I wouldn’t want to know the details of self-abuse. If some feature changes the nature of the act, such as it involved self-exposure or peeping, just to name some possibilities, I’d specify that it included “self-exposure” or “peeping”. I would not detail anything beyond that unless the priest needs to know more and asks you. If it included peeping, for example, I would mention whether I have dealt with the near occasion (if it is a neighbor). If I was doing self-abuse and I’m married, I’d tell him I’m married. Beware the risk of reveling in salacious detail!
No, if I had to confess abusing another person, I would not provide details of how I did it beyond that it was a beating, rape, etc. If it involved kidnapping, I would include the word “kidnapping” and the age of the victim. I would detail the time frame (minutes, days?), any other crime connected with the incident, like blasphemy, theft, lying, etc. General detail, but not specific.
Say what it takes to specify the type, nature, and gravity of the sin. Also say what it takes for the priest to offer doctoring for your soul. Do not run the risk of firing anyone’s imagination with excessive detail, unless neccesary and warranted.