Sword Art Online - Aincrad Night Of Kirito summary:

When Kirito took on a random quest on the 76th floor to kill time, he didn't expect to be transported to a bedroom and find himself wearing pyjamas. To his surprise, the One Thousand and One Nights quest summons various girls that he is acquainted with, all of whom are tricked into thinking that they have to share a bed with Kirito to complete the quest. The true goal of the quest, however, is for Kirito to survive till morning without getting into bed with them. If he fails, there will be a penalty for the girls...