Today is the first day I came to my girlfriend's house. She lives with her older sister Mei, who is a nurse and often works night shifts. Whenever tired, Mei usually falls asleep deeply on the sofa. She wears loose clothes that reveal her big breasts in front of me. I always try to control myself, but when my girlfriend had to leave urgently, I couldn't resist anymore. I unconsciously approached her, my hand had already touched her big breasts without me realizing it. As I fondled those big breasts, Mei seemed to show no sign of waking up. So I became more daring. I buried my face in those big breasts, sucked on them, rubbed my penis against them, and Mei still didn't wake up! At this point, I could be completely at ease, proceeded to insert my penis into her wet pussy...