Before you start up a match go into the rules and disable all items besides pills, and this will make it so that a bunch of pills will spawn inside of the laundry room.
Pick up a bottle of pills and feed them to the baby by using the X button. The pills should disappear if done correctly. The game can bug out and sometimes this randomly won't work. If it stops working restart the game.
Alternatively, you can enable only Fruits, Bleach, & Pills and grind out all 3 at the same time.
If you run out of an item simply quit out and reload the level and the items will respawn.
You can check out my quick achievement walkthrough here if you need anymore help.
Intro 0:00
Baby's On Fire 1:45
What's Cooking? 2:22
Deez Buffs Make Me Go Nuts 2:42
Iced Iced Baby 3:38
Turn a Rat into a Snack 4:10
Baby's First... 4:43
5:20 Rules For Grinding 25 Fruits / Pills
Riding Dirty 6:09
Attempted Vehicular Infanticide 6:55
Life's a Bleach 7:11
Fruit Based 7:34
Doctor Daddy 7:50
I'm Your Daddy 8:18
Daddy Let Me Drown Grind 8:35