He's so happy he didn't even care about the fact his buddy banged his crush.
It's a bit of a translation contrivance on my part. All that's implied is that Masashi likes this girl named Mika, not necessarily in a particularly deep or romantic way. Didn't know how to get that across without sounding forced.
I was about to release this as a typeset 2-koma but then I decided to check it. Your second speech bubble is a made-up rewrite.
スピーカー で 流すなり して, 気 を 利か せ なさい よ ホント 使えない わ ね.
In the second speech bubble mayuri is saying that the headphones are leaking like speakers.
Notice how in the first panel, there are small bubbles around the boyfriend which imply sound is leaking.
Also notice that there are no speakers anywhere in the background, therefore the boyfriend simply increased the volume of his headphones to make fun of mayuri comparing his headphones to speakers.
At its most literal I interpret スピーカーで流すなりして to mean she's telling him to "let/make [the sound] 'flow' through/with [a/the] speaker(s)". 流すなりして to me sounds like she's telling him to do it. And "speaker" can just mean the phone's built in speaker. She's also chastising him for not being tactful and letting her hear, and between that and the volume being suggested in the second panel I don't think it makes sense to turn up the earphone volume instead of letting the sound play through the phone's speaker. My Japanese might not be great, especially when it comes to grammar, but I see nothing there to suggest such an interpretation. I don't think anything in the phrasing is comparative or alluding to the earphones being like speakers and I'd expect to see something like 漏れる rather than a more deliberate sounding 流す if it really was trying to convey the sound being "leaked".
Is there a Japanese term for headshot? I always sorta wondered that.
Not unless you go with a literal "Being shot through the head" sort of translation, no. They just use the English term, and being in English probably makes it sound a bit cooler too.
The artist has included no less than 32 variants of this image in the gallery. I don't have enough uploads to post them all even if I uploaded nothing else, so if someone wants to upload them all, please do. Otherwise, check the pixiv link for everything.
