Not really a trust exercise, but it definitely helped bring me and my SO closer in terms of communication and intimacy, which leads to trust - for a while, we'd do things that I found to push my limits. Not hit them, exactly, but just, "wow, that's just a touch uncomfortable, but it's okay, I'm dealing, it's fun and you get off on it." The edges of limits, if you will. Recently I've been doing things to him that push against the edges of his limits (anal play with him receiving), and it's really enjoyable, because we have to be in such sync, since he's experienced anal but only in passing. Lots of, "Is this okay?" "What about if I do this?" "Or this?" and watching his face really closely for any sign of unhappiness.
