Tora To Ukigumo

Naotora is the young leader of the Kinosaki-gumi who runs his territory with pride. One day, he stumbles upon a massage parlor and falls asleep under the treatment of Ryuji, a male masseur who seemed a little suspicious. When he wakes up, he felt something strange, and it turns out Ryuji is inside him! He thought it was a regular massage shop, but it turns out to be an illicit sex parlour, and Ryuji even discovers Naotora's secret ED problem...?

(Source: Takeshobo, translated)