What type of writing technique does Curtis use to convey the theme, as shown in the evidence? “I spit a big glob in my hand and said, "We're brothers forever, Bugs!" We slapped our hands together as

What type of writing technique does Curtis use to convey the theme, as shown in the evidence? 

 “I spit a big glob in my hand and said, "We're brothers forever, Bugs!" We slapped our hands together as hard as we could and got our slobs mixed up real good, then waved them in the air so they'd dry. Now it was official, I finally had a brother!”