The song is "Kiss the Girl" from The Little Mermaid movie. The scene is during lunchtime at Hogwarts and Draco is admiring Hermione from across the room. He wishes he could kiss her but he realizes that he is Serpent while she is a Lion and the two could never be together.
Oh and the word "dissed" is American slang for the word disrespect.
There you see her
Sitting there across the room
She don't got a lot to say
Well at least not to you
And you don't know why but you're Slytherin pride
Won't let you
Kiss the girl
Yes, you want her
No denying it you know you do
But she's never gonna want you too
Makes no sense to ask her
You don't say a word
Not a single word
But you should kiss the girl
Sha la la la la la
My oh my
Looks like that Malfoy guy
Ain't gonna kiss the girl
Sha la la la la la
Now he's mad
No one to blame; too bad,
shouldn't have dissed the girl
Now's your moment
Better hurry up before you're doomed
Boy you better do it soon
Maybe send a letter?
And when she sees the words
It'll change her world
And then you'll kiss the girl
Sha la la la la la
Think he's scared
Slytherin's unprepared
He'll never kiss the girl
Sha la la la la
You're not allowed
She doesn't want you now
Oh yeah, you've missed the girl
Sha la la la la
You don't belong
Just listen to the song
Why would you kiss the girl?
Sha la la la la
It's not okay
Coz she's a Mudblood babe
Need to resist the girl
You'll never kiss the girl
You make her want to hurl
You pray to kiss the girl
You'll never kiss the girl
Okay thats it. i had fun writing so I hope you had fun reading.