some switch stories?

http://www.mangago.zone/read-manga/satou_kun_ni_wa_kanawanai_sachimo/ (Oneshot & 3p)
http://www.mangago.zone/read-manga/bad_prince_honey_party/ (ch. 2~3 for kinda a switch; 3p)
http://www.mangago.zone/read-manga/neko_x_neko/

Or look at these tags:
▹ Switch Couples: http://www.mangago.zone/tag/switch+couple/?page=1
▹ Seke: http://www.mangago.zone/tag/Seke%20/
▹ Switch:
http://www.mangago.zone/tag/Switch/

http://www.mangago.zone/read-manga/dark_heaven/