I'd rather not being heard or signaled to it either, and I probably would never tell that to friends or neighbors. But nonetheless, hearing it happens often, and some people aren't ashamed of talking about it, and giving away a sextoy non-used would be ok for them too. Everybody has their own sense of intimacy. That's not too unusual. It's just that in this story they are very open about it from one side or sometimes, like some real life people are too. And they became friends fast enough to do some cringey things like this. Not my thing, but not so weird either.
I have friends who probably could be a little like that, but none that are neighbors.
it's weird lol. intimate stuff should be done and talked about with your partner only. sure there's more to it, you can discuss sex with others but there should be limits to what you can say or else might as well just call it an open relationship with how everyone is up your business.
don't forget all these people are GAY. if my girlfriend was given a SEX TOY by someone who is attracted to women when we're all adults i'd be furious idc. maybe i'd be fine with that if they were actually friends for life, but the person giving it to her being a "friend" who she knew for like 3 months? i'd allow that if i were polygamous and was open to welcoming others i guess
I actually don't see where they "have fun hearing" each other moaning. :/
And I would be a lot less ashamed if it's was newly knowned and friendly neighbors that told me they could here me, and vice-versa, than my old friends. It could actually be a weird but fun and awkward way to stand in the same awkward ground and become friends. (I say could, not that I imagine it'd be easy for someone like me who has trouble handling a sex scene on tv with someone near me already ><)
I again, don't know where you're from, and I don't judge, but even I, as a rather prude person in real life, don't find that all surprising.
That said, I think there is a gap between how you've perceived some interactions in this manga, and how I did personnaly. ;)
(Also, English isn't my language either XD)

i like the manga but there's a thinly veiled exhibitionism? kink going on in here that's lowkey a huge turn off for me ugh. why do we have to know that their neighbours hear them all the time and are nosy about it too lol