The description doesn't help, this is from the official website:
あらすじ
「私の犬になって」心に闇を抱えた少女ふたりを繋いだもの…それは「首輪」と「赤いヒモ」だった――。母を亡くし父子家庭で暮らす女子高生の結。一見平凡な生活を送る彼女には秘密がある。…それは、父親への緊縛行為。そんな彼女はある日、街で同級生のつかさを見かけ、その光景に目を疑う。それは、つかさが大人の男性に首輪をつけ、散歩する姿だった――。
With roughly translate to (google):
"Become my dog," connecting two girls with darkness in their hearts... a collar and a red string. The result of a high school girl who lost her mother and lives with her father. She has a secret in her seemingly ordinary life. …It's a bondage to his father. One day, she sees her classmate Tsukasa in the city and doubts the sight. It was Tsukasa wearing a collar on an adult man and taking a walk.
I don't know if it leads to yuri later on (apparently? according to the tags and such) but it's a wild start.