What are the monks in Monty Python and the Quest for the Holy Grail saying?

They say some Latin stuff, and then they hit themselves on the head.

What are they saying in Latin? And what’s the English translation?

From this site , Recursion:

I was going to type the translation but I got distracted by a German porn site…

Whoa, I posted just a matter of minutes ago, and I already have the answer. Thanks a lot!