I have UC (or possibly indeterminate colitis i.e. possibly crohn's colitis) and I regularly press when I am flaring- I don't know why, but I guess it is to sort of gage what is going on too. In my case, if a flare is developijng I can normally confirm this by feeling the abdomen "crunch"- literally crunch- when I press in. I am not sure what the crunching is but I assume it is pockets of little air bubbles that form amidst the inflamed tissue, or perhaps it is the abdominal wall's reaction to changes in vascularity that accompany a flare.