I heard something about you have to go less than 24 km/h. During a leisure bike ride, I at least managed to hatch some eggs and get the tracker to count the distance.

A safety tip is just to open the app and then put it in your pocket with the touchscreen facing outwards. If inwards the heat and sweat from your thigh can actually interact with the screen.

If you're going to do this, also turn on power saver option, and put it in your pocket top-down - that mostly turns off the screen and should save quite a bit of power on AMOLED screens, though maybe not so much on LCD.