I with most bottoms so far. I can tighten it up or let it loose. It all depends on the top and how they enjoy the hole they are fucking. However, in my expierence, I've had tops who while they were fucking me or they took a pause for whatever reason but were still in me and I tighten my muscles, most tend to roll their eyes back as if they had never expierenced a bottom doing that before. I've also noticed, at least with me anyway, that the length of the dick also comes into play, if they are to short for my big ole bear butt, they tend to pop out when I tighten up so for a smaller dick I usually don't do it while they are actually fucking me. THis probably wouldn't be a problem for most of the bottoms here, since most of you are on the thin side and have cute firm little ass'.