No. Some people can find that weird and some can argue it's not apropriate to do personal hygiene on the kitchen but that's not different on Europe or North America IMHO. Just talk it with your roomate and maybe you can get an agreement. I can guess the need can arise in a small apartement with lots more people than bathrooms. If your room mate continues to disagree propose to use a bucket.
Edit: Yes I live in Brazil and has lives here for more than 30 years in many towns in Northern and Southern regions. Also has traveled a lot and know a bit of the main cities like São Paulo, Rio de Janeiro, Salvador, Curitiba, Porto Alegre, etc.