As the only son of a yakuza boss, Ranmaru Oumi is set to marry his childhood friend Kaoru in an effort to unite their families - but he's not happy about it! When a wedding night spat sends Ranmaru to the cruise ship's bar, he meets Alberto "Al" Valentino, an Italian man with a love of all things Japanese. Between Kaoru's bossiness, fights with a rival gang, and Al's unexpected advances, Ranmaru is sure to have a honeymoon to remember!
Both are BL/shounen-ai/yaoi OVAs that are 2 episodes long. Also, both anime involve yakuza. They are also both cute and funny. If you like one, you will probably like the other.
Ikoku Irokoi Romantan is similar to Tight Rope since there's yakuza involved, and one character is more 'cold' than the other. But... in my opinion, I'd say IIR has more a more intense storyline. But it does share similiar characteristics to Tight Rope. :)
Both of these OVAs are about the beginnings of a homosexal relashionship from the view of the "uke" and neither are overaly sexual. If you enjoyed one, you'd probably enjoy the other (the quality of Tight-Rope is much better).
I think that if you liked either one of these animes you will like the other one because they also most have the same plot to it. Also the main characters like each other but don't know what to do about it really. But in the end they go really well together.