To make a fool of yourself, often associated with inappropriate sexual comments or gestures and general foolish behaviour. The word is believed to have evolved from the name of the now extinct Quacha which was a mix of a neighing donkey and a barking zebra. Proper use is in reference to ridiculous postulation and acting the fool.
"Look at him, the big old gwaga!"
"What's with the gwaga attitude this morning?"
"I don't believe it, she's so horny she's acting like a gwaga!"