Otokonoko wa Hachimitsu

From Eclipse Scans:

Minoko accidentally witnessed the secret of her junior, Akane, whom she has been hitting it off with. This Akane is much different from usual, and Minoko involuntarily...?!

Compilation of short stories:

• Honey Prince
• Magic Red Thread
• If I Disappear
• Trembling Honey Taste
• My Honey Sweetheart