Cheer Up Thwomp!
From the Super Mario Wiki, the Mario encyclopedia
Cheer Up Thwomp! is a minigame found in Mario & Sonic at the Olympic Winter Games. To gain access to it, the player must have Princess Peach in their team. In Frostown, there is a Thwomp blocking Mario and Sonic the Hedgehog's way. If Peach is in the team, Toad will suggest to let her cheer him up, so he may get out of their way. Peach agrees, and this minigame starts.
To win the minigame, the player has to fill the heart meter within the time limit. To do so, they have to blow into the mic to make Peach's hearts hit Thwomp. However, he must be hit when his eyes are open, or the energy in the heart meter decreases. When the heart meter is almost full, wind blows in the opposite direction of the heart's path, serving as an obstacle.
Hit Thwomp with hearts when its eyes are open. Stop when they close, or it'll get mad!