How do you leave someone a message on Twitter?

[4inthemorning22]

This is driving me insane! I wanna leave my friend a message...so I go to his profile, and do the arrow thing, and leave a mesage...but the message is written on my wall! I want to be written on his wall! How do I do that?

Thank you

p.s. I posted it on here because a lot of ppl come here than the 'internet' section

[sarjinderkaur]

Your message when you hit reply, will show @friendsname and your comment. It will show when he logs in to this too. But its not like facebook, that you can post on his wall. It's not the same thing. It's just a status update software. He can see what you wrote though.