excited about something
worried about something
anxious, uneasy or impatient
unable to keep still
The children have ants in pants as their exams are over.
I am excited about my birthday and have ants and pants.
Do you have ants in pants? Stand still while I take your measurement.
Dave had ants in pants as he could not wait to attend the new class.
Not every idiom has a literal meaning. This idiom has a literal meaning that one cannot stand still if ants get into one’s pants.