That Time, My Mother-In-Law Seduced Me... Iroha Fukuyama.

My wife is pregnant and due to give birth soon. The three of us—my wife, me, and my live-in mother-in-law—went to the hospital. But there were no signs of labor yet, so my mother-in-law and I returned home. At dinner, my mother-in-law said it was still fine, and we had some drinks together. When I said it felt like I was doing something wrong, my mother-in-law kissed me, saying she'd do something even more wrong. Her kiss was lewd and exciting, and since I'd been neglecting my wife, I got hard immediately. Then my mother-in-law, looking pleased, took my thing in her mouth and slowly sucked it. Unable to hold back, I came, and my mother-in-law started sucking it again. Then my wife called. I answered in a panic, but my mother-in-law, still looking pleased, buried her face in my crotch and started licking again...