My sister-in-law is soaking that I can't masturbate, and I sway my hips and gently cowgirl position

I was hospitalized and was unable to move my hands due to an injury and was forced to abstain from masturbation, and I couldn't hold it in, so I asked my beautiful, busty sister-in-law to help me have sex alone, even if it was no good... and it was unexpectedly OK! She secretly scrutinizes her injured body in the hospital, treating her slowly and gently, then straddles her and swings her hips into a slow cowgirl position. At first, she reluctantly arched and fully erect cock, but her step-sister gets serious in her sticky, gentle cowgirl position, and she can't hold back and ejaculates inside her vagina!