I've had "multi-dom" sessions, three being as a "practice sub" for a "Mistress-in-training." The first three were with my first Mistress, the late and legendary Belle de Jour from Manhattan. My first time as a "practice sub" was my SECOND session. After that first session with Belle as a 20 year old college kid, I was so turned on, but had no cash immediately, I'd call up a couple of times a week just to hear her voice. After three or four of such calls she barked at me on the phone, "GET HERE AT 4 TOMORROW AFTERNOON! I'M TRAINING A NEW MISTRESS!" Turned on, but intimidated since I barely had money for one tribute ($35 for 45 minutes in 1973!) I gulped and whispered, "I can't afford the two tributes." Belle barked again, "JUST GET HERE AT 4 PM AND HAVE MY TRIBUTE!" I got there, went to the playroom, and Belle would politely tell me how to stand, bend over, etc. but was pretty direct with the Mistress-in-training. Halfway through the session, Belle said, "That's it for today," to the trainee and she went one-on-one with me, firmly in control but both seductive and warm with me. It was a unique experience, just like Belle herself.
A decade later I got back into the scene, became a regular of her niece, Gloria, who Belle introduced me to at her dungeon. After one session Belle said, "My friend wants to become a Mistress and I'm training her. Can you come to my apartment?" I said sure, her place was a couple of blocks away from the dungeon. I seriously don't remember if a tribute was involved. If so it was minimal. We played in Belle's living room and bedroom and she demonstrated different aspects of dominance that I was comfortable with, then the trainee would repeat it. I remember her friend being excited and turned on, with more vanilla reactions than a real dominatrix. A second lesson a few weeks later took place, this time Belle was there only in the beginning and another Mistress did the instruction. Ironically she was a dancer I met at my friend's bachelor party a couple of years earlier. At one point the Mistress tied me to a wooden chair with the trainee, then telling her how horny I got at the bachelor party and I got groped by both of them. Yes, another unique session and a lot of fun.
The final time as a "practice sub" was a bit strange. It was a few years after Belle. It was a Mistress Tyra, who was in Manhattan a bit during the '90s. We did the "Amazon Queen / captured Tarzan" role play and asked if a trainee could sit in and watch. The key piece of equipment was bondage bench with a cage on the bottom. Tyra put a collar and leach on me, something she never did before, and whipped me into the cage. I was ordered to growl like an animal, tried to grope Tyra's legs, she whipped my hands and I acted like I could "bend" the bars and escape. I was removed from the cage, leaned me over the table and Tyra showed how to hand spank and ass whip a sub. The trainee had the look of shock and surprise. She said little. Halfway into the scene Tyra dismissed the trainee. The door closed and she laughed, "I don't think I'll see her again." I was rewarded with foot and leg worship for the punishment I endured.
One other two-on-one session was one an escort/dominatrix arranged with another pro who heard about my roleplay. I went to the pro's apartment, they had a large plush tiger for "Tarzan" to wrestle. They had on leopard or tiger two piece outfits, I had on a homemade leopard thong, and there was a lot of spanking and growling after the tiger was subdued. While the ladies were gorgeous, my memory of the session was that my attention (lust) was split between the both of them and I didn't know who to give attention to first. It was like having too much ice cream!