Resizing an image larger to fit on many pages. These are then printed out and placed side by side to recreate a large poster of the original image. Usually the image is also modified to be made up of smalldots, similar to old comics.
"That poster is huge, it must have cost you hundreds."
"No, Wendy taught me about rasterbating, it only ended up costing like $10."
To wander whilst masterbating. Frequently performed by those who get distracted easily and need a change of scenery. Painfully awkward for room mates, houseguests, parents, etc.
I once walked in on my brother while he was masturbating. Wait, I walked in on him while I was masturbating. I was wanderbating.