Here is an FAQ for Pyrex plugs I found while digging on the net.
http://www.allglasssextoys.com/cart/faq1.php
(Of course as it is off a product site, it plugs - pun intended- their name continually in the FAQ.)
But borosilicate glass is quite strong. Just as long as the piece has no flaws - chips, cracks etc. - then it should be fine. I've never had an issue with mine at least.
Oh and TG - does your love of Pinky and The Brain extend to The Animaniacs?![]()