I have not done it myself, but a contender for the best idea a woman had while trying to engage my kinks was the Cadbury egg trick. She occasionally put one or more inside her blouse just before going out to shop or run errands. Even when she was bold enough to forego the use of a jacket or coat to conceal the mess, it was never much of a spectacle.
Yet the psychology of it really tickled my fancy. She could never be sure just when body heat would melt the chocolate and transform a slightly odd sensation into a rush of sticky ooze. To know what she was feeling with so many unfamiliar eyes upon her excited me. Of course, once home we were free to make the most of that excitement, and there was no reason not to incorporate trashing clothes already stained by the melting eggs.
Regards,
messydom
P.S. I wonder if any choclatiers are among us. In part this is because working with chocolate seems like a natural draw, but also because it occurs to me that there might be a niche market for specially designed treats meant to be worn more than eaten. If Cadbury came up with such messy fun by accident, imagine what experts dedicated to the cause could accomplish.