Supplementary Investigation: Off-Duty Gavan Episode 15

Setsuna tells Rui that after their most recent mission, he learnt about cosplay and got interested in it. Rui, noticing that he's already wearing the costume he wore for the mission, takes off her police uniform and reveals her own costume under it. The two start dancing, but Gavan Amigo enters the room. She uses Emorgear Hatenzoda to put on a princess costume and starts dancing as well. Setsuna and Rui are amazed at her dance. She then takes off the costume, revealing a simple loincloth underneath it. Setsuna takes off his own costume and remains in only the loincloth that Rui gave him earlier, much to her horror. (Source: Project R.E.D. Wiki)