Napalm is an incendiary, not an explosive, i.e., not a bomb.
Fuel-fertilizer bombs /are/ explosives, however. They do indeed go "boom". I first learned about these from an online friend in Appalachia who related the story that among his friends, one of the things to "do" for fun was to make one, drive into a disused mine, drop it off, and let it go boom. This was years /before/ the Oklahoma City bombing. Yee-haw.
Mix Styrofoam and gasoline (as much as you can dissolve), however, and you do get a sticky burning substance - good enough for most campfire lighting purposes (summer-camp way - a can of spray wax and a match) or self-immolation (someone actually did this in Wakefield RI, for really stupid reasons). Add elemental phosphorous for extra fun.
One of Fieser's colleagues suggested adding phosphorus to the mix which increased the "ability to penetrate deeply...into the musculature, where it would continue to burn day after day."
"Napalm sticks to kids"
I cannot find any chemistry (from something /not/ related to the Anarchist's Cookbook or some-such Darwin-event inducing text) related to easily making a bomb out of TSP, so unless you have a reliable reference for your just-so-story, I have to call  on this.