You can freeze the sticky rice and reheat whenever you want some ice cream Thai style; it doesn't even have to be with coconut ice cream! But it's important to freeze the rice in portions, otherwise it'll be stuck together in one big block and impossible to break apart. So make little 1-serving clumps then freeze them in a freezer bag or container, making sure they don't get squished back together during freezing. To reheat, cover the rice with a damp paper towel and microwave for 20-30 seconds. Take it out and stir it to even out any cold spots, then microwave again for another 20 seconds or so until the rice is steaming hot. This timing is for small amounts; if you're reheating a lot, it make take a lot more time of course. Keep in mind the rice will not regain its sticky and soft texture if it's just warmed. It needs to be steaming hot, and then allowed to cool back down to room temp before putting ice cream on it.