As a kid I got constipated several times a year so my mom started to check most evenings. At bath time, she'd look at my underwear to see if they were soiled, especially if I seemed 'out of sorts'. If she thought i was actually constipated, she'd tell me to sit on the toilet and try to go.
When I was sitting, she'd get a plastic pitcher out from the cabinet under the sink, drop in a bar of Ivory hand soap, and fill the pitcher with warm water and put the pitcher on the counter and leave, telling me not to wipe or flush.
After a few minutes, she'd return, carrying a box with a bulb syringe, or, as I grew older, a flat blue box with a Rexall Roxbury fountain syringe. I was told to stand and she'd check for results. She'd then tell me I could wipe and flush, or 'you didn't try hard enough. You need to be convinced to go now.' and she'd fill either the bulb or the bag.
I had to stand, feet apart, bent at the waist, hands on the toilet seat while she squeezed several bulbs full into me. Later, I got a bag full of the warm, soapy water from the bag in the same position.
The solution always 'convinced' me quickly and powerfully.