“good day for making dung”

The Lao language is very similar to Thai, so we were able to just about make ourselves understood. My favourite Lao/English conversation was:

James: “can I please have a hot chocolate now and a beer Lao after dinner”.
Friendly Lao Manager: “If I drink beer before food cannot wake up and have bad day for making dung.”
James: “ hhmmm”
Manager: “If I drink beer after food and then sleep is good day for making a dung”

Was something lost in translation?!?