Why would a Japanese adult be embarrassed to use the word "friends"?


I am watching a current anime, _That Time I Got Reincarnated as a Slime_ (
転生したらスライムだった件 ). The protagonist, now a reincarnated slime in the isekai
story, is making friends with a dragon. The specific conversation begins at
time code 20:30 of [chapter 1](https://www.crunchyroll.com/that-time-i-got-
reincarnated-as-a-slime/episode-1-the-storm-dragon-veldora-777519)*. After
they have agreed to be friends, he thinks to himself (sub, time code 21:17):

> いい年して『友達』って、ちょっと照れるけど…。  
>  It's a little embarrassing talking about "friends" at my age...

He was 37 when murdered. **Why would he be embarrassed to use the word
"friends"?** Is there a better word to be used between adults?

* * *

* Link is to Crunchyroll, an American streaming service. I don't know what other countries will be able to view it.

This question is a follow-up to [What is Japanese version of the pun word,
“slife”? … and term for adult
friend?](https://anime.stackexchange.com/questions/49183/what-is-japanese-
version-of-the-pun-word-slife-and-term-for-adult-friend/49192). On Anime &
Manga SE. @кяαzєя answered it, and he suggested I post a follow-up question
here.




> いい年して「友達【ともだち】」って、ちょっと照れるけど。

The word _tomodachi_ ("friend") itself is not really embarrassing, although
there is a more [formal word](https://japanese.stackexchange.com/q/18312/5010)
for this concept. In this case, this _tomodachi_ also represents the whole
exchange he has just made with the tsundere dragon. Indeed, innocently and
directly saying 友達にならないか ("Let's be friends!") is not something a typical
middle-aged man would do, at least in Japan. It sounds to me like what a
kindergartner might say. Usually such a relationship between adults starts
without mentioning the word _tomodachi_. (By the way, the situation is
different [when it comes to romantic
relationship](https://www.tofugu.com/japan/kokuhaku-love-confessing-japan/).)




> いい年して「友達【ともだち】」って、ちょっと照れるけど。

The word _tomodachi_ ("friend") itself is not really embarrassing, although
there is a more [formal word](https://japanese.stackexchange.com/q/18312/5010)
for this concept. In this case, this _tomodachi_ also represents the whole
exchange he has just made with the tsundere dragon. Indeed, innocently and
directly saying 友達にならないか ("Let's be friends!") is not something a typical
middle-aged man would do, at least in Japan. It sounds to me like what a
kindergartner might say. Usually such a relationship between adults starts
without mentioning the word _tomodachi_. (By the way, the situation is
different [when it comes to romantic
relationship](https://www.tofugu.com/japan/kokuhaku-love-confessing-japan/).)

