Lesbian curiosity

Hi, I'm straight and married.
I've got a colleague who is a lesbian and she's constantly talking about how much she enjoys using a dildo. I'm not very educated on the sexual life of a lesbian (obviously) so I was surprised by this because she's not into men but she likes to use a penis shaped dildo for pleasure.
I am just curious if lesbians do have sex with their girlfriends by using penetration with a dildo or just use foreplay. :)