How do I talk to girls when I am quiet?

I'm an 18 year old boy who has never had a girlfriend before and has very few friends who are girls. I have no close friends who are girls. This has generally been due to me being a shy person.



However, since I've started university I have made an effort to meet some girls in my lectures. I have talked to a ton of girls recently and had some really good conversations which I'm really happy about. I have even made a few them laugh a lot which felt really good.



Even though I am shy, when its only me and a girl talking I seem to be fine talking to them. I can sound interesting, make them laugh and be slightly flirty/cheeky. However, the problem is, when my friends are around and involved in a conversation with these girls I completely dry up and cannot think of a thing to say to her.



So does anyone know why I may dry up like this or does anyone else have the same thing happen to them?



Does anyone have any tips for me then please?

How do I talk to girls when I am quiet?
You have to open your mouth and say wordsHow do I talk to girls when I am quiet?
you should just stay calm and think of things to say and don't dry up.
Faint heart never won a fare lady.