When I first started I had very painful skin irritation from using a one piece Hollister system that didn't vent. Literally a baggie with an attached flange and no vent for gas. Horrible.
By the way, for me, using a generic antacid that is anti gas works well as a bag lubricant. Years ago the home health nurse suggested that I use mouth wash. Not a best choice for me at all.
I take a hot soaking tub bath with stoma completely exposed before changing out the flange. Have a hard plastic cover with a waistband that I use over the flange for showering. Not perfect but helpful. If I get the tape around the flange wet it leads to early failure.