My pelvic floor PT taught me a different technique than the ones described here. She told me to start with 10 diaphragmatic breaths, then rest your right hand on your lower right abdomen for 10 more diaphragmatic breaths. Then make radial motions from your navel across your belly in every direction, like you're drawing the sun, as many times as feels right. Then knead yourself like a cat would, starting low on the left and pressing toward your groin, moving your hands incrementally up your belly and still pressing toward the groin, then switching to the right side & pressing towards your ribs when you get to the top of your belly. After massaging each of the left quadrants, slide your hand down the whole quadrant. After massaging the top right quadrant, slide your hand upwards and across the top of your belly. Slide your hand upwards after the lower right quadrant. Then, starting at the bottom right and moving counterclockwise, press & slide your hand across your whole colon 10 times. Her thinking is that it's like a traffic jam, and to clear a traffic jam you'd want to move the cars in front first.
She told me to do this massage before bed so that I'll have a good BM when I wake up for the day; we do a lot of our digestion overnight. Sometimes it takes me 10 minutes, sometimes it's more like 30; it depends on how "knotted" and gassy my guts are. It's quite effective at getting gas out immediately, and it definitely helps some with stool, though I'm still much more likely to have a BM late at night rather than soon after getting up, cuz that's just how my guts work.