Kago no Naka no Ω: Yasashisugiru Sokubaku

Aya, an Omega, loses his memory in a traffic accident. When he regains consciousness, he is taken in by Haruto, an Alpha doctor who stays by his side. Haruto says that they were in a romantic relationship, but Aya can't remember anything.

When the two of them return home, he suddenly begins to experience heat symptoms. As Aya desperately searches for a suppressant, Haruto slowly pushes him down from behind... "You don't have to take it," he says, covering Aya's mouth with a kiss. Then, as Aya goes fully into heat, he passionately embraces Aya's throbbing body...

(Source: BisouBisou Comics)