Mu5hr00m,
It's hard to quantify, because it varies from one play partner to the next. With some women, I am 100% Dom, others, perhaps will sub occasionally. There are a few women with whom I am 100% sub. I wish I could be more clear, but honestly, I don't know what triggers the submissive side.
I understand, as it's hard to quantify for my switch desires as well. Fortunately I enjoy both sides, so either type of partner's desires are fine. For LT partners I do prefer a switch partner since I do like to do one side or the other at various times.
Interesting experience/story about 20 years ago. I answered a personal ad on the old Beth Tyler site for a Domme who liked giving enemas. After we texted and trusted each other I drove to see her. She was a very good enthusiastic Domme enema nurse and the first session gave me a long rectal exam followed by a supine enema with me dressed all over in neoprene rubber and sneakers (two other major kinks). The second visit she made me be naked wearing only high top sneakers, tied me up a bit and gave me three consecutive enemas that day. One was on my back, next on all fours and the third forcing me to sit on a bulging JBL bag, my first, with her masturbating me on the bag until I finally orgasmed after the bag was empty.
While we were lying naked together after I emptied myself, she really surprised me by telling me something unexpected. She said I was a really good sub and she'd really enjoyed Domme-ing me and wanted to do it again, as I did too. Believe me, I had just been my normal self, a very compliant but also very vocal submissive (moaning, groaning, pleading for leniency), enjoying it tremendously. The unexpected part was she also said that something had clicked for her (to this day I don't know what) and she also wanted me to Dom her and let her enjoy being sub sometimes. So for several months after that we traded visits and also traded roles and we both really enjoyed both sides. Just as an example, the first time she wanted to sub to my Dom I dressed her completely in a neoprene rubber suit and sneakers, put her limbs on spreader bars, put in a urinary catheter and gave her a big enema. We both loved it.
So after that and still today I just get to know someone and decide between us who is in the mood for what on any given day and Dom(me) or sub as we like it. Obviously both desires are there for me and deciding how to give both people the most pleasure and satisfaction determines how we act and play.
My last two exes have both been switches and we've had a really intensely good time doing either role with each other, though I tend to do more subbing usually.
Eric