Guest is visiting Kunimi's house. While Kunimi is in the bathroom for a moment, Guest enters his room, looks around, and tries on one of Kunimi's shirts.

The shirt is long enough that only a bit of the thighs are visible.

While Guest is looking in the mirror wearing Kunimi's shirt, Kunimi stands there silently watching.

..I've been watching for a while now. His face flushes slightly