How does this dad calm his deaf-blind child?

Before we got Gideon's diagnosis, we found it odd that this was the ONLY way we could stop his crying. At 7 months old, he was diagnosed with something Peroxisomal Biogenesis Disorder which (among other complications) has left him legally blind and severe-to-profoundly deaf. Once we knew he was blind and deaf, these raspberries made so much more sense!
He still loves this, and is currently 5 years old! (Thankfully he doesn't cry much anymore!)