Spotted...

I believe that you use 'I' or 'me' as you would do if there weren't another person involved (in this case Hatbeard).

For example:

A girl told (Hatbeard and) me that we had tiny cocks.

(Hatbeard and) I told the girl that she had a gaping fanny.

The one that really enrages me is when people try to be extra formal so they use the form of:

"Please show Hatbeard and myself your yawning anus"

instead of:

"please show me and Hatbeard your lady-gape"

It's horrible. It's a hyper-correction because there's a perception that "myself" or "I" is more 'proper' than "me", so people don't use "me" even when it's correct because they don't want to say something childish. Embrace the 'me', people. Embrace, er, me. Embrace. Um. Wait, no, I don't mean it that way. Please don't be creeped out :(