I placed it on the outer part of my arms close to the shoulder where it's the most fatty. Because triceps skin is too thin and it needs a bit of fat to work well. Place a work over patch on it and it will not budge.Nice. Just got 2 months worth.
I sweated, showered with it not had a problem once.
Know that the first 24 hours gives completely random values.
I suggest you place the CGM and don't pair it for 24hours so it doesn't skew your statistics. Just let it do his things for 24hours then pair it and see how it goes, check with a blood glucose meter if the CGM it's accurate in giving you BG reading. Check only when BG is stable so when you are fasted and not after eating or during. Or while you exercise etc.
If the readings are far off you can calibrate it. Don't calibrate it too many times or it fucks with the algorithm.
Once is great and check after 12hours again accuracy.
Remember if you press with your weight on the part where the CGM is attached it can gives you low readings