What does ヘニャッ mean?


What does ヘニャッ mean in the following sentence?

> やっぱり甘えたいと思う時あいますよね。疲れている時とか、 **ヘニャッってなりたくなる** 時。




I agree with Chocolate that it is 擬態語. Thus if I understand correctly it is a
sibling of onomatopoeia, but not quite the same thing, because ヘニャッ doesn't
come from sound.

The mental picture this word should evoke is something soft that buckles or
collapses. So in the context of what you provided, I think it's a (tired)
human body that buckles (onto the lap of the girl/boyfriend or something like
that I'd imagine, since you say 甘えたい)

