Dear Ian:

The Church teaches that what we must confess in the Sacrament is the kind and number of our grave sins (venial sins may also be confessed in the Sacrament).

For example, let us say that I shoplifted at each of the following stores: Sears, Pennys, Office Max, and Walmart. The confession need not mention each store, but rather the kind (shoplifting) and the number (4 times). If the priest asks which stores then tell him but otherwise it is sufficient to say, "Father, bless me for I have sinned. I have shoplifted four times this past week."

Now with that said, as to your specific instance. Do not worry about whether a sin is mortal or venial. If you thought to place it on your list, then confess it. It is good to bring venial sins to the Sacrament as well. The Sacrament is a healing Sacrament. Even with venial sins, it helps to heal the wound caused by the venial sin and to give you strength.

Thus, when you make your list, put down whatever it is on your heart to confess. If a few venial sins get on the list, that is okay. When in confession, do not second-guess yourself. If you have it on your list, go ahead and confess it.

Now, as to the specific sin of dirty-jokes. In my personal opinion, the telling of a dirty joke is of a different "kind" that that of "lustful imaginations" or thoughts. Lustful thoughts and imaginations that are entertained in your mind come from things like watching a movie with a nude scene, seeing a pretty girl on the street, fantasizing about a favorite movie star or other such thoughts which you entertain lustfully in your mind.

Telling a dirty-joke is more than a lustful thought. It is inspiring lustful thoughts in others through humor. In my opinion, that is a different class (kind) of sin.

If it were me, I would confess the sin of telling a dirty joke the next time I went to Confession.

As far as if you committed sacrilege by receiving the Eucharist, I do not think so. If you were honestly thinking that the sin of telling a dirty joke was already covered in your confession, and you were not consciously and deliberately withholding this sin from your confession, then technically when the priest absolved you, this sin was included and you are free to receive the Eucharist. BUT, if you now realize that you should have confessed this sin specifically, then you do need to confess it before the next time you receive the Eucharist.

That is my take on this anyway. When you go back to Confession you can ask your confessor about this and see what he says.

God Bless,
Bro. Ignatius Mary