You mean slowing down the swing meter speed, right?
You can buy "advanced" balls in the pro shop. They all have different meter speed indicated in their stats. The higher the number, the slower.
There are also clubs you might consider to slow down the meter speed but be careful! The swing meter speeds of some clubs are even faster than the (default) starter clubs you have so it'd be better for you to rent and experiment them by yourself before you actually buy them. Generally speaking, based on my experience, clubs with swing speed 4.0+ are the ones you will see some significant swing speed decrease.
Another option is "Focus Buy Boost". It'll cost you 30 credits each time and be applied only once on that particular shot. Tap on the swing meter and you'll see the lightning icon right above the meter. I've never used it so frankly I can't tell how effective that is though.
↓↓ EDIT : You know what, Scott and Steff... I thought the same at first, but then, I said to myself "Maybe, just maybe he might be real" so I wrote what I know. And thanks, Nico. I appreciate it. :) ↓↓