I don't understand the thing with the teddy bear??

Im pretty sure it was a gift from fuyuki during the chapter when it was raining and saw them kiss for the first time

Yeah but that's Fyuki's home, if the teddy bear was a present she gave to Eri why it's there?

She didnt give it , Fuyuki throw it away bcus that guy and Eri became lovers so the guy give her Eri the exact same bear