Ren felt the resistance of Ryuu's tongue against his own which lit an even bigger fire in him.

He slid one of his hands from Ryuu's hair to his neck and went inside the fabric of his yukata. He let his hand slide down even further, by that undoing the yukata of the man beneath him. 
On his path down, Ren came across a small bud and decided to fondle it, hoping to get a reaction.
Ren looked at Ryuu with his deep emerals eyes through his long, black eyelashes. No reaction.
He did it again and saw that Ryuu was holding his voice and reactions back.

A bit annoyed by this, Ren bit Ryuuho's lips and slid his hand further down where he fondled the submissive, yet embarrassed boys behind.