Meaning of “tag along” - Learner’s Dictionary

tag along

informal phrasal verb with tag uk us /tæɡ/ verb [ T ] (present participle tagging, past tense and past participle tagged)

to go somewhere with someone, especially when they have not asked you to:

If you're going to town do you mind if I tag along?

(Definition of “tag along” from the Cambridge Learner’s Dictionary © Cambridge University Press)