At the same time, fellatio from three twins
Those are triplets;
Action is getting some oral pleasure from triplets. Saying ‘three twins’ however, implies that there are 3 sets of twins, making the situation that much better.
Triplets could also be a reference to the use of three rhymes over the two lines (“Timbs”, “Wynn”, “twins”) Although technically not a poetic triplet (or “tercet”), which is a stanza of three lines, Bronson seems to be making a point of that sort.
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