The only one i know is this very short one shot with a tiny uke sleeping in slipper. Is it maybe this one?
http://www.mangago.me/read-manga/k_sensei_no_yajuu_na_aijou/tr/145363/page/173/
Oh god how could i forget, sorry! the prequel is in the extras of this one
http://www.mangago.me/read-manga/k_sensei_no_yaban_na_renai/
please help.. im looking for a yaoi manga.. uke is a chief at some company, and seme is his subordinate.. the uke turn into mini human and sleep inside a slipper at the seme house i think ??