Both mangas involve the semes in an organization/occupation where they use their ukes for ulterior motives. Initially, both semes do not realize their attraction for the ukes.
The uke is more feminine in DOnS but both ukes are known to be gay prior to their relationship with the seme.
The ukes' cute naivete and honest, straightforward characters are similar. So are the semes' pushiness and possessiveness. Both mangas exploit this setup with skill to create some really amusing situations.