Do I need special lubricants ?
Absolutely not! Glass is also amazing because it is non-porous. Unlike silicones, it absorbs nothing. Use your favorite lubricant, saliva, water, or nothing at all. 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 are even beautiful enough to be displayed!
is the glass cold ?
Short answer - YES ! If you want them to be. Another amazing quality of glass is that it retains temperature. Cool them in the fridge or freezer OR reheat them in a bowl of hot water to start. Absolutely play with the different temperature sensations. But when they are used, once they get to body temperature, they stay there and it's so nice.
A little note to remember: when going from cold to hot, give them a little time to reach room temperature.