Many people find cool sensations are very pleasurable especially if you are warmed up. The difference in temperature arouses nerve endings which makes the area more sensitive to stimulation. Cold touch also can calm you after the first round and make ready for the second one.
Important: Don't cool your toy in the freezer because objects that are too cold can stick to your skin.
We love warm sensations. Warmth brings blood to the surface making the area aroused and engorged. You instantly become more sensitive to stimulation. Warm play can really speed up things for you making you more aroused.