Something I think would sound better is: When you sing ‘sister’ and ‘twister’ hold the first syllable a little longer. This sounds great, and will also accentuate ‘Wow Mr’ since that line will still be delivered rapidly.
Also, hold ‘twister’ when it comes back later, too.
This is just my personal opinion of course. But I think I’ve got a decent ear for catchy pop, especially lyrics.