I don't understand...

[olydiagron.livejournal.com]

Однажды "языка" я добыл, да не донес.

It is from the song "Tot, kotoryi ne strelyal"

Oh, and one more question, about the "pesnya-skazka o nechisti":

Налил бельма, ишь ты, клещ, - отоварился!

What is бельма? is it gentiv of бельмо? I can't make it make sence...