Chocolate Days

The protagonist is Mogami Takuya, your basic cliche average high school student, whose mother is passed away and father is away on business. There are five very cliche women in his life: an older friend from childhood who calls herself his sister and takes care of the household, a Kansai-ben beer-loving older cousin who lives with them, a nymphomaniac teacher, and two twin sisters who are students a grade above him. The game basically follows his life surrounding one of the heroines for the month of February, with several different text choices on each route.

[description from Boys' Love Games Headquarters]