Belonging Is Difficult

I may be really off-base here, but I find the verb belong to be strange, as it seems that its present participle form is not really ever used -- at least, it doesn't sound right to me.  It is okay as a gerund, but not as an actual verb.

These sound perfectly fine (non-present participle):

I belong in that group.
The dog belongs in a nice home.

These sound totally wrong, but I admit that they are probably grammatically correct:

I am belonging in that group.
The dog is belonging in a nice home.

As a gerund, it sounds fine as well:

Belonging is important.
Belonging to that group gives him special privileges.

I couldn't think of another verb where the present participle sounds really wrong and awkward.

Anyway, I found this to be strange.  Any other verbs out there that are difficult in this way?