Can u guys suggest me something were uke and seme exchange positions (seke)?

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

Dark heaven
Haru wo daite ita

Plus this list. It's really a good list. You should check it out!
http://www.mangago.zone/home/mangalist/33677/

ff

http://www.mangago.zone/tag/seke/
Here you go.