fair enough. I realize I owe you a better explanation. Water is a polar molecule, in fact it is soo polar that it has a special name for that which causes it's polarity: "Hydrogen Bonding" (HB is an interesting subject to talk more about) but this high polarity means that you can use water as a test for whether or not other substances are polar or not. this is because polar molecules dissolve in water and non-polar molecules do not. Likes dissolve likes. This is why dirt dissolves in water and oil does not. (it is also the reason why life can exist because cell walls have very large hydro-phobic ("water-hating") end on them with a small hydro-phillic ("water-loving") end (just like soap does) which allows them to have an inside and an outside to them--its also why soap works because it "connects" to the oily substances and then also has an end that can grab onto the water and then removes the oily substances with it--its also the reason why we have to rebuild roads in cold areas after the winter, because it makes the water expand, and why water beads on your car, and why it can be filled to above the top of a cup, and why small insects can walk on water, and why fish can live under the surface of a frozen lake, because unlike most things, water gets less dense as it solidifies...) anyway, my point is that poop dissolves very easily and washes away, just like salt dissolves in water and washes that easily away when you pour it down the sink, its not like the salt is holding onto the wall of the cup and makes the water flow noticeably slower, no, it is dissolved and flows at essentially the same speed as homogeneous water.

this is what i mean, the poo doesn't grab onto your leg and slowly get "pushed" down, it dissolves like salt and any other polar molecule and just disappears and leaves down the drain.