pettishly

/ˈpɛtɪʃli/
adverb
  1. In a way that shows childish annoyance or bad temper over small things.
    • He pettishly pushed his plate away because the toast was slightly burnt.
    • The old man pettishly complained that the music was too loud, even though it was barely audible.
    • “I don't want to go,” she said pettishly, crossing her arms.