tagalongtag‧a‧long /ˈtæɡəlɒŋ $ -lɒːŋ/ noun [countable] 
1British English something that is attached to and pulled behind something else: 
The tagalong attaches to an adult’s bicycle.2someone who goes somewhere with someone else: We were tagalongs on my parents’ vacations.
1British English something that is attached to and pulled behind something else: The tagalong attaches to an adult’s bicycle.2someone who goes somewhere with someone else: We were tagalongs on my parents’ vacations.