I ship it means that you think one person and another will be good together or that they are going to get together, or you’re just plain annoying and want to make someone go insane *covers face in shame*. You can even ship ppl from different universes, for example you COULD ship an anime character with a book character, but that’s just plain illegal and a big sign that you could be a rly terrible person.
Me: *sees person talking and laughing with person, and them smiling back*
Me: *mutters under breath* I ship it ÙwÚ
Them: *months later start dating*
Me: I knew it!!!!!
Everyone else: ............... 911? Halp, we got a crazy person
A phrase used for certain Harry Potter couples and pairings that you adore so much to the point where saying 'I ship it' becomes an understatement, hence, the use of 'I Durmstrang ship it' becomes more appropriate.
Because the Durmstrang ship is a magical ship and can travel underwater, it implies that a particular pairing is magical, can survive everywhere (on land and underwater too), and you will always ship it, no matter what.
Potterhead #1: 'I Durmstrang ship Romione and Jily so much!
...
Potterhead #1: 'Do you ship book Hinny?'
Potterhead #2: 'I Durmstrang ship it! It's my OTP!'