The protagonist has been in a relationship for some time but he has been holding back on anything sexual for a while. One day, his slightly S neighbor, who happens to be an older sister figure, tempts him with sexy voice of her. Despite his attempts to resist for his girlfriend’s sake, the older sister won’t let them go and wants to “milk” him until he get satisfied. The protagonist can’t help but imagine what it would be like if this older sister was his girlfriend instead, and she promises to do naughty things with him every day. The protagonist’s rationality is pushed to the limit as he struggle to resist temptation, but he eventually succumbed to the older sister’s seduction. MC’s suppressed desires finally reach the limit.