Yes she has. I'm sure the experience varies from guy to guy.
For me when Nikki ko's me with this hold its not painful at all. Usually she locks it on and I know I'm in trouble cause I know it's coming. Her version is inescapable cause her legs are so strong so I usually try to talk her out of knocking me out. When that doesn't work I start begging. It goes something like this:
I begin feeling woozy. Nikki isn't squeezing real hard yet. Just kind of holding it and making me squirm. The dialogue goes something like this:
Me: please Nikki I don't want to get knocked out again.
Nikki: I don't care what you want Assclown it's not up to you.
She increases the pressure a bit and I try to start rolling my hips in a futile attempt to escape.
Nikki: (laughter) do you really think that's going to help you Assclown?
Me
lease I can't take anymore Nikki?
Pressure increases.
Nikki: I really don't care Assclown.
Pressure increases and I'm really fighting consciousness. I get my hands inside her legs for one last escape attempt.
Me
lease I can't breathe Nikki
Nikki: (more laughter) that's kind of the whole point isn't it Assclown?
Me
at the top of my lungs) NIKKI NIKKI NIKKI NIKKI
I wake up to Nikki holding my face with both hands. It's a rare moment of in session compassion from her. I don't know where I am and as I start to realize what happened and get to a seating position Nikki locks on a rare naked choke and the process starts all over again.