The very first thing I think is, "Fuck." That thought repeats itself randomly throughout. After that it's just a series of attempts to gain or maintain a certain level of control over myself and the situation as a whole. I focus on my own breathing, any other sensation I might be experiencing like something in my hand, trying to figure out a pattern to what the ler is doing so I can be ready for it, making any movement that I do discourage the ler from getting near spots I want him to stay the fuck away from, etc.
If I get past that control freak part, (which is fairly rare), it depends on the behavior of the ler. If he's quiet and just going about his business I probably don't think much. I just enjoy the sensation. If he's bantering and talking shit, I get a little more competitive and think about what to say to gain the upper hand. If he's being teasing and playful, I usually just kind of get into whatever he's saying or doing. If I feel like he's working his way toward one of my panic spots, that's usually when I return to the cursing and try to find a subtle way to distract him or redirect his attention to something else - usually pretty effective 😀 I'm kind of a mind ninja.