It looks like she’s drinking from an icicle? If the icicle in question was one of Cirno’s wings, would that make this lewd? I’m asking for a friend.

I don't think it's meant to be lewd. It looks like she's cupping her hands by an icy stalactite, the heat from her hands would make it melt and that's the water she's drinking from.

Added the commentary to clear up what it's supposed to be.