Mamakatsu Hajimemashita

She found herself recklessly lusted after by a young man… with her body splayed as he took her vigorously. She knows it isn't right, but... she feels so fulfilled when he comes inside of her...

(Source: Coolmic)

Notes:
- Includes one extra chapter.
- Originally serialized as a web manga under the title Hajimete no Mamakatsu kara 2-jikan-go…: Fuufu no Shinshitsu de Netorareta Hitozuma no Kiroku (初めてのママ活から2時間後…夫婦の寝室で寝取られた人妻の記録) in long-strip and traditional formats simultaneously, with 36 episodes and 12 chapters respectively.