Put two pillows (preferably fluffy ones) down on the bed, one top of the other, and then slip your penis between them. Prop yourself up on your arms and begin to pump. This is a free-handed technique.
PILLOW ON DESK
Simply put the pillows on a desk (most desks have the right height for this) or a table, place your hands on the pillows, and insert your penis and thrust in and out. This is something like having "doggy-style" sex.