Seke couple mangas?! (They are so rare, man lol) I've already read Ogeretsu's Reversible

http://www.mangago.me/read-manga/doutei_doudeshou/
And in the sequel they switch
http://www.mangago.me/read-manga/doutei_doudeshou_dj_another/

Thank you!

Look at this. You'll be surprised how many of Seke.
http://www.mangago.me/tag/Seke/

What does seke mean?

seke = seme uke. both have the position to be either seme or uke, so the roles are reversible. in other words, one can be bottom and then the next time they have sex that person can be top.