How do you guys keep the analog stick in place while doing M-speed? I find that my finger always slips and I mess it up. Any tips or does it just come with time?

All comes with practice

Alrighty, thanks. Also you were a huge inspiration for me to start running, so I thank you for that

Yes, there is tip. If your finger slips - put him under the stick, not on stick. Things became so easy. Just look at xrrstyle But muscle memory is main point.