You are free to discuss your confession with others. I can’t see why anyone would think otherwise. When I made first Reconcilliation, we were discouraged from discussing it with our classmates, but that was to discourage childish talk of “what did you confess?” and more drastically, “whadidya get?”
I can see a benefit to being able to discuss your confession… if I went to confession with a priest other than my own (or my spiritual director or regular confessor), I would find some real benefit to being able to discuss the sins confessed, the priest’s counsel, and the application of the penance with my own priest.
In fact, the last time I visited my parents, I went to confession from the priest I grew up with. It was not only beneficial to discuss confessions with my current confessor, it was beneficial to discuss this particular confession with my current confessor. It helped paint a picture of a pattern of sin and the steps being taken to correct the pattern. Both priests are extremely excellent confessors, and I feel like a better person for this experience.
Now, the seal applies to a Penitent if they overhear someone else’s confession. If you are at the head of the line and you overhear the confession of the person in the confessional, the seal extends to you.