It's unclear how to edit the title of this entry. The main title is transliterated incorrectly. It's supposed to be "Pink no Ken", similar to Hokutou no Ken (Fist of the North Star). "Kobushi" is incorrect.
Anyway, there are three entirely separate stories in this volume. Overall they're pretty cute and funny. Nothing mind blowing. If you've read multiple other works by Watashiya, you might like this one too. While this was originally serialized in Flower Comics and is supposed to be shoujo, her penchant for racy humor certainly comes through. My favorite of the three stories was actually the last one, Boku no Kusuri wa Amakute Nigai. It's a cute love story with good characters.