The best MFM experience was the very first. It was my very first 3sum, and so it was my first double penetration.
I had several wonderful orgasms, but the one I experienced during my first DP I remember as being the most intense of my life, maybe because it wasn't expected?
The worse?
There were one or two that didn't go well, due to some problems between the two men, the "my turn" thing.
I think the worse 3sum was when the men were so afraid of each other they stayed apart, so I was just traded back and forth, with no real chance to have them both at once.
One particular experience while I was on vacation in Pensacola FL would be the worse time. They argued about "who's turn" all night. One took me to the shower, so I could go down on him, then after he came, the other fucked me on the bed, then out on the balcony. As the night went on they got drunker and drunker, and ended up mostly just cuming on me, on my boobs tummy and bottom, etc.
I woke up next morning on the balcony, naked on a chaise lounge, covered in dried semen, with a horrid headache. They were nowhere to be found.

WW

__________________
"I wondered, am I a lesbian, am I straight, or bisexual? Then I realized that I am just a slut.
So where's MY parade?"

---Margaret Cho