The simple fact is that not everybody likes everything. That being said, if you have a good and long term relationship with another person and you want to do something unusual, or that might hurt a little or have some short term discomfort, or be a bit degrading.. I dunno, if you wanna do it once in a rare while, it would be nice if your partner would accommodate you just out of kindness.
Over the years I have done a lot of things that I was perhaps not in the mood for but my partner was and my attitude was always we don't do this every day, just grin and bear it. It wont go on forever and it will make my partner happy, and it won't kill me.
I can see for example not liking the after effects of hard anal sex. I can understand the bottom feeling that for a while after the fact, but splooging on her face? The after effects are like minutes.
And as far as the stinging goes, either close your eyes or look at it like any of the other little kinks you indulge in that hurts. I am amazed at the number of painful kinks I see people talk about on here, and yes some make such a big deal out a something less burning than getting shampoo in your eyes.
I would not spooge on a womans face who would not be willing to take it once in a while, but I also would stay away from a woman with such strong binary feelings as far as what can go where.