My wife was away, and Rino - her younger sister, was traveling nearby and wanted to stay at my house for about four days. This sister-in-law has a very strange hobby... being completely naked while inside the house! Walking around naked, her G-cup breasts constantly shaking in front of me. Furthermore, Rino purposely creates provocative poses, touches me as if teasing me! On the last day, my endurance reached its limit. I ignored everything and continuously had sex with this seductive sister-in-law! We entwined with each other without stopping, and as a result, I ejaculated inside her ten times! When she returned, Rino asked me if I could come back to her again. Despite knowing how morally wrong this is, I couldn't think much, I wanted to enjoy this pleasure more. And so, I agreed to her expectations.