Happy End no Kyuseishu
Nao is a college student who draws indie eromanga. The morning after a grueling deadline crunch, he finds a little snakey boi, which invites itself inside his room. During a nap, it starts sucking on Nao's willy and gulping down the seed… and of course Yasu, Nao's kouhai, walks in.
Dismayed as he is by Nao deciding to keep the tentacle as a drawing assistant and manga inspiration, Yasu lets Nao use his hand to jerk off every time it's time to feed the now-named 'Wiggle-michi' its semen.
Truthfully, Yasu has always had a crush on Nao.
Could this sentient tentacle be their cupid?!