Hey there!
A verb is an action word. A verb just means that the word is something that requires an action to do, some examples are: run, jump, play, eat, drink, walk, etc.
The verb in this sentence is teases.
When you tease someone, it requires an action to do. You're probably making fun of them, or something of that sort. In any event, it is an action word.
Hope this helps!
