Taking care of glass is a lot like upkeeping your hygiene. Joint wax is like chapstick for your lips. This wax provides a coat to your ground joints and helps to prevent the glass grinding or breaking from frozen joints. You simply apply a large coat of wax onto the male joint and twist the joints back together whilst trying to maintain an even spread all sides.
Love your glass, clean it and maintain it for a long, sturdy and healthy relationship.