Take another look at the sentence:
My cat Fuzz sprang onto the kitchen counter, strode to the sink, and flinged herself onto the cool porcelain for an afternoon nap. Only here was she safe from the pursuit of Oreo, the dog.
The third verb, flinged, is the problem. The sentence requires the simple past. Flung is the correctly spelled form.
|Verb||Simple Present||Simple Past||Past Participle|
Sprang, the verb you chose, is perfectly correct. Before you continue, review the rules for irregular verbs.