@dirtwizard666 @vantablack Yeah, gonna want a silicone, PVC thermoplastic, or natural rubber sleeve on those. Like a hot/cold water bottle, but a leetle bit thinner. You want it to feel cold, but not enough to damage mucous membranes by prolonged contact.

Actually, might be better if factory sealed and filled with encapsulated phase-change material with melting point at 5 °C.