Myself, I have a "genitals do not belong there" kink which goes along my "grotesque looks" one. As for how it works, I very much prefer it when it's caused by a transformation and might be reverted after a while (e.g. due to lack of randiness that made one's mouth change shape in the first place), especially because not being able to speak properly when the smut is over is something which bothers me. I guess that's why >>1750 is my favourite type of pussymouth. Now that I think about it, that could be the only instance of deepthroating I'm interested in.