Use 'sheepish' to describe someone who is slightly embarrassed but not deeply ashamed. After tripping on stage, she flashed a sheepish smile to the audience.
Pro Tip 2/3
Self-conscious Behavior
'Sheepish' often implies a person is aware of their awkwardness or mistakes and feels uncomfortable. He had a sheepish look when his voice cracked during the speech.
Pro Tip 3/3
Mild Discomfort
It describes a temporary state, not a person's overall character, and is not very intense. Her sheepish grin didn't last long before we all laughed off the incident.