Kenna gives Erin a sensual massage, and gets permission to roll the privacy towel down little-by-little to massage more of Erin's body. There are hints of Kenna being attracted to Erin's towel-covered butt... and when Kenna gets permission to fully remove the towel, it's revealed that Erin is wearing a butt plug!
Erin admits that she's seen Kenna's attraction towards her butt before, so she wanted to give her a sexy invitation to take things further, starting with an extra cheeky butt massage. Kenna is surprised, but with some encouragement, eagerly agrees.