Probably, anyway.
Or at least Ashitaka
At least shown briefly. http://www.mangago.me/read-manga/bond_z/an/bond-z--chapter-1.html/33/
Terrible dynamic, of course...
Really seme x seme
Maybe - the 2nd couple discusses it for the future...
Rather than seke couples being shown, a couple of them are cool with whatever. Mostly smut.
*Update - seke couple with switch during the one sex session.
Hatsukoi No Atosaki