Give other internet users slower speeds

My sister is always watching vids and eating up my speed. How can I make her usage slower? Many thanks!
Answer #1
it’s not really your speed, but you could install netlimiter on her computer… (only if she agrees to!)
Answer #2
Hah, she’d never. But I’m connected straight to it and shes connecting wirelessly.
Answer #3
your router may be able to do the trick, it depends if it supports limiting different mac adresses.. try looking for such a thing in the router settings..