Weighted Ball workout (long toss or pitch)

I always hear that long toss is what helps you gain velocity but I never hear why long toss helps gain velocity more than just pitching. I have a weighted ball program I do in the summer and fall but now since its winter its harder to get outside. So I put up a matteress against the wall in my basement and I now thow against it every three days. I wanted to know if I should simulate pitching against the matteres by going through the windup and everything or should I pretend like Im long tossing and just throw the ball kind of high like I would outside when long tossing instead of low like you do when pitching.

weighted balls should never be tossed like a regular ball and should never be tossed with a wind-up. if you want to throw it throw it like an infielder and never do so on a mound.

If I use a regular 5 oz ball should i pitch it or simulate like im long tossing agains the mattress. Which is better to help gain velocity

“weighted balls should never be tossed like a regular ball and should never be tossed with a wind-up. if you want to throw it throw it like an infielder and never do so on a mound.”

Says who?