Do I need special lubricants?
Absolutely not! Glass is also amazing because it is non-porous. Unlike silicones, it does not absorb anything. Use your favorite lube, saliva, water, or nothing. The other advantage of this non-porous material is the smoothness with which it glides.
Glass just needs soapy water and a place to rest. They're even pretty enough to put on display!
Is the glass cold?
Short answer - YES! If you want them to be. Another amazing quality of glass is that it retains temperature. So chill them in the fridge or freezer OR warm them up in a bowl of hot water to start. Absolutely play with the different temperature sensations. But when used, once they reach body temperature, they stay there and it feels so good.
A quick note to remember: when going from cold to hot, give them some time to reach room temperature.