It's google serving you ads based on the sites you visit. Clear your caches and browser histories to start. Factory reset your phone and stop looking at p0rn if it persists.
Ads on YouTube help support the creators you love and let billions of people around the world use the streaming service. When you block YouTube ads, you violate YouTube’s Terms of Service. If you use
support.google.com
Blocking ads is against goggle's terms of service. You must watch them.
Substitute "google" for "the party" when you read this article