We had a bonding moment. I cradled you in my arms bq.

On June, 20th 2016, Netflix aired a season of Voltron Legendary Defenders that gave way to unexpectedly create one of tumblr's biggest ships (a.k.a Klance, the pairing of Keith and Lance).
In the episode "Taking a flight", Lance has made a full recovery after being wounded in the previous episode.

Transcript:
Keith: I punched Sendak!
Lance: Yeah, apparently after I emerged from a coma and shot his arm off.
Keith: We had a bonding moment. I cradled you in my arms!
Lance: Nope. Don't remember, didn't happen.

This one sentence sparked countless memes and fanart, even being referred to in many non-voltron fanfic.
For a ship that started in June 2016, the overwhelming popularity is quite impressive, and presented how quickly the show has gained traction.

Gayest scene in voltron that began a wave of pointless fangirling/fanboying

At the end of the episode it's revealed the Lance remembered the bonding moment, but wasn't emotionally stable to go there.

Usage and appeal of the meme:

Ever since that episode the fandom had never been the same again. Klance has shot to popularity so quickly is that it fits in with a lot of established ship tropes. The red/blue colour combo, love/hate antagonism, fire/ice, and loud/quiet personalities are all hallmarks of many popular canon heterosexual romances in media as well as LGBT ones.
The sentence is often used in many LGBT fanfics.