My jealous sister, Kawagoe Jinko, is always staring at my morning erection to prevent me from having sex with my girlfriend. (SONE-628)

Now that I'm in college, I can finally date the girl I met in the club! While excitedly looking at my phone… "Brother! Are you secretly dating someone you don't know about?" For some reason, my little sister, who likes me, is bursting with jealousy! "So that my girlfriend and I can't have sex, you're having sex before our dates!" My morning erection is completely drained every day!!!