Love Lab. This manga is a collection of stories by Momoyuki.
Story 1: Love Laboratory
A rare hormone solution had been invented by the chemistry club. Per bottle costs 500 yen. Boyfriend of Riko-, Yuuki-himself is exceptionally cold towards passion. Riko-hopes to push their relationship one step further but ultimately...? (Source: guinea pigs)
Story 2: Merry Kiss
A stunning model, Saya-chan, has been paired with Natsu, the #1 having lusted after celebrity to create a passionate ad campaign.
Will the two couple fall in love with the fake kissing scenes and artificial love scenes?
Story 3: Perfect Doll
Kenji's father told him to go to Japan and conceal his identity as a puppet master until they got separated. Otherwise, the black master would come after him. Renji promised he would and he plans to do it, but now he's losing students in his school, and when they come back they're dead as if their soul had been ripped away from them like a doll.
Story 4: Twinkle Twinkle
Student by day, enigmatic Star Drop thief by night. Mashiro must steal all of Reira's treasures to open the old town road she believes her father is on.
Story 5 - Cupid's Love Arrow:
She was the matchmaker in residence before he arrived. A transfer student pretending to be a fortune-teller and supporting girls with their love issues. Trying to see if it would work out one of his spells, Aya inadvertently summons Mira angel-in-training to their world, and she discovers the truth. Now she knows why he was such a good Cupid because he himself was the read item!