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WARNING!! This question and answer is of a mature nature. Parental discretion is advised.

Dear Jack:

You need to drop your fears. No confession is made invalid because you did not reveal the nitty-gritty details.

The Church requires that we confess kind and number. Masturbation is the "kind". It does not matter what methods of masturbation that you employed. Masturbation is masturbation.

Number can be an estimate of the number of times if one does not know the actual number. That estimate can be like, "I masturbated three times a week." Do not obsess over the actual number. If you do not know the actual number, then make a general guess.

While this is all that is required by the Church, if you wish to tell the priest the "methods" of your sin, you can. That is okay. It is a personal choice.

While confessing "method" is okay, there is a danger if we begin to "explain" the sin. "Explaining" is in essence searching for excuses. If we explain why we sinned, the circumstances of the sin, and whatnot, that is trying to mitigate our responsibility for sin. It does not matter why one sins, or what the circumstances were (e.g., I was tired, he insulted me, I was stressed out, etc.), sin is sin. It is the sin we confess not the whys, wherefores, and circumstances. Thus, we need to avoid "explaining" our sins as that is really an exercise in trying to negate one's responsibility for the sin in some way.

In your case, we are not talking about "explaining" but about confessing the "method" of your sin. That is not needed, masturbation is masturbation regardless of method, but you may reveal the methods if you wish.

This is advice for the future. As for the Confessions you have already made, they are valid regardless of whether or not you confessed the "method."  There is no need to re-confess or do a general confession because you did not mention the "method" employed in the sin. You are okay. Move forward.

God Bless,
Bro. Ignatius Mary