Possible Clues:

• Tucked-in clothing part
• Tee's usual lack
• It may stick out of one's pants
• Tucked-in garment part
• Garment part
• Garment part that's tucked in
• Young and immature
• Irish stew with latte almost causing one to tuck in?
• Dishevelled, his attire endlessly left ... this showing?
• It's usually tucked in