I'd recommend not only asking, but also answering others' questions. It's not the same as having a group of people that you regularly talk to, but it's something.
You could also hire a graduate student tutor. For example, here is a list of math grad students at the University of Wisconsin willing to do this:
This is difficult. One way to do this is to participate on Math Stack Exchange:
https://math.stackexchange.com/
I'd recommend not only asking, but also answering others' questions. It's not the same as having a group of people that you regularly talk to, but it's something.
You could also hire a graduate student tutor. For example, here is a list of math grad students at the University of Wisconsin willing to do this:
https://www.math.wisc.edu/tutors
An hour every two weeks would go a long way.