Set up your ladder under the damaged area. Scrape off all loose stucco from the area using a drywall knife. Make sure the remaining stucco around the edge of the damaged area is solid.
Open your stucco and bring it up the ladder.
Scoop up a trowel-full of stucco with your cement trowel and press it to the ceiling, in the middle of the damaged area. Spread it on the ceiling so it's about 1/2-inch thick and covers the entire area where you scraped off the damaged stucco.
Work the stucco into the same pattern as the surrounding stucco, using your trowel to swirl, pull or randomly line the wet stucco.
Allow the stucco to cure for three or four days. Paint the whole porch ceiling, using a thick-napped roller to get the paint into the crevices of the stucco.