On our last blog, we learned how to say "be my guest" when someone asks to borrow or use something that is ours. Similarly, we can also say knock yourself out although this is more informal and is used mostly with friends. Knock yourself out also means "Sure, go ahead" or "Sure. Help yourself."
A: Is that your laptop?
B: Yeah. Do you need to use it?
A: Can I? I just want to check my email.
B: Sure. Knock yourself out. I don't need it right now.
A: Thanks. I'll be quick.
B: No problem.
Alright folks, don't forget to practice. ... and the next time you're hanging out with friends, look out for chances to say knock yourself out.