Looking for holy grail tips... getting antibiotics into a 3 month old?? Help, 27 doses still to go!

Little guy has a kidney infection, he's high risk for those due to a congenital kidney condition. He had IV antibiotics at the hospital so far, but now we need to give him antibiotics 4x a day for the next week.

I tried going slow and doing little by little into his cheek, but he still spit some out. I was going to try alternating meds with nursing next time, but I'm not sure if that will make him mad. I'm also waiting to talk to a nurse at his ped, but was hoping there are other tips and ideas out there to try!