https://www.dlsite.com/maniax/work/=/product_id/RJ01517027.html
https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_658470/

[Synopsis]

Kocho Rinko, a mother of one and happily married to her beloved husband, had only one worry weighing on her mind.
At the request of her best friend, Uzuki Rio, Rinko agreed to attend a cosplay event for the first time in years.
Yet, as she donned the provocative costume, the lewd stares that gathered around her and her own insatiable lustful body began to ache dully and sinisterly.
After the event, Rinko and her friends headed to a hotel room, where an obscene, immoral photo session dubbed “after-party” began...
The butterfly, shedding its cocoon drenched in lust, sucked and savored the milky nectar with its ripe, swollen mouth, slowly and thoroughly learning the taste of unfaithful honey with every fiber of its being...

This is a tale of infidelity in which a former cosplayer, now a slutty wife with a child, is tricked by her wicked cosplayer friend into having sex with a huge dick off-camera.
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''The butterfly, shedding its cocoon drenched in lust, sucked and savored the milky nectar with its ripe, swollen mouth, slowly and thoroughly learning the taste of unfaithful honey with every fiber of its being...''
Damn, what a paragraph!?

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