Final answer:
The correct verb form to fill in the blank is 'tocamos'.
Step-by-step explanation:
The correct verb form to fill in the blank is tocamos. The subject 'Mi hermana y yo' is plural, so the verb should also be in the plural form. 'Tocamos' is the first person plural form of the verb 'tocar' which means 'to touch' or 'to play' in English.
Learn more about Verb forms in Spanish