(tl;dr: I am not threatening my kid with the knife, it's a tool. If you're gonna read this thing, read the whole thing)
As I stood in front of my calm, smiling child with the exposed blade of the knife from a multitool in front of me, I considered for a split second how I arrived at this point.
Sure, he is a fine child, and I love him dearly. He's getting physiologically ready to potty train, and what comes out down there is always a surprise, both in quality and in quantity. Today is no exception.
Before me, I am confronted with a quiz. You have a nearly two year old in front of you, whose plain undershirt onesie he's been running around in is a faint brown color near his nether regions, but they can only be practically removed by pulling the item over his head. This has been easily done in the past, but today, he's outdone himself. The entire bottom is soaked and the area you have to unsnap is also a brownish color. He thought it best to hide from you while doing this, since he of course wanted his privacy. So you decided to declare the onesie a loss, as it's the cheaper undershirt kind anyway.
So you size up the situation, note the boy hasn't been squirmy and is very interested in what you're up to. So you pinch his shirt near the belly, and with the sharp side toward yourself, you make a 4" incision from the center to the left side across the shirt, and close up the blade, putting the multitool back on your belt. With some easy tearing, your son now has an exposed midriff, and the bottom portion slides safely off via his legs, as he patiently smiles.
Now you remove the diaper, which is apparently more… well, liquid than usual. It's clearly… soft. Mixed with a bladder full of urine. Which explains how the mess happened so quickly.
Slipping both off, wiping your child from the bellybutton down, front and back, and up the legs to the feet, you begin to wonder when he'll be able to communicate his need to use the restroom before he does it. Soon, hopefully.
Disaster averted, you play happily.
Now I don't say this stuff to discourage procreation. Not by any means. I love my child, worked diligently with my spouse in a long term loving relationship to have him, and plan on eventually having another.
But when you think to yourself "boy, that condom sure is a pain in the ass, I'm sure we'll be okay just this once" I want you to consider that visual for a moment. If you're cool with that, with the partner you're with, by all means, have at it. If you're not, well, trojans are the same cost as that onesie, when both are purchased in quantity.
Be safe out there and have fun!