Fechippuru ~Our Innocent Love~ summary:

I love long hair! Tatsu Yunoki, our MC, who deeply loves the beautiful long female hair, heard a voice scream his name, it was Kotoka Hatsushima, and under the impulse of alcohol, both he and she, decided to date together. All they know is that they love each other's hair and back?! It’s not necessary to know anything else! They clash fetish against fetish, and come together in a fun and romantic comedy! And well... What is your fetish...?

You can read it online for free in the link. That's a good thing, 'cause is probably the first mainstream comic about long hair fetish

mangakakalot.com/read-si0rm158504884602