I Couldn't Wait Reiko Kobayakawa (2019)

Reiko Kobayakawa is a married woman whose husband is away on business. She is having an affair with her former manager, Katagiri, who has erectile dysfunction and needs treatment. As they engage in a titjob, Reiko finds herself enjoying the attention and intimacy, highlighting the central kink of the movie as a cheating wife scenario with a focus on oral sex.