To slide into a particular mood, attitude, or situation means to gradually start to have that mood, attitude, or situation often without intending to. She had slid into a depression = slip
When something slides somewhere or when you slide it there, it moves there smoothly over or against something. She slid the door open I slid the wallet into his pocket Tears were sliding down his cheeks
A slide or bottleneck is a small tube of steel or glass that fits around one finger This can be used to fret, but instead of pushing down on the fret board, you "slide" around on the strings to produce a particular effect Its quite often used in blues and country Check out Sheryl Crow, "All I wanna do" on the Tuesday night music club album which has quite a lot of slide on it
the act of moving smoothly along a surface while remaining in contact with it; "his slide didn't stop until the bottom of the hill"; "the children lined up for a coast down the snowy slope"
If you slide somewhere, you move there smoothly and quietly. He slid into the driver's seat