It often--though not always--provides characters that are almost all male.
It sometimes--though not always--includes a sexual relationship between the main male characters.
A Gentle Noble's Vacation Recommendation does not include a sexual relationship (as far as I know).
The similarity is that in both cases, the relationship is completely taken for granted--it is a given and, in Hanger, a matter of necessity, not a matter for angst or pondering or conflict, by either men or women, boys or girls. The stories are primarily action-oriented.
And yet the relationships are vital. They inform the decisions of the main characters--often in terms of responsibility and protection.
The best overall description here is bro-romance. Joey and Chandler with weaponry, complex villains, and more odd pets--and only once does one of them actually move out (until Chandler gets married and even then, he tells Monica, there will be an "apartment over the garage for Joey").
There's a Bones/Booth element to Shonen since the relationships are never in doubt, never threatened, never in danger of breaking even if they don't proceed to romance. They just are.
