義理のいとこが私の家に泊まり、誰も家にいない間に彼女をまさぐりました(捕まりそうになりました)。

The tension was impossible to control. While my guest was resting at home, the horniness won us over: forbidden caresses, intense touching and stifled moans so as not to be discovered. The morbidity of almost being caught made it even more exciting.