Ms or old school speed is all ive heard of people using to cut or jump with. When meth is cut with Ms especially if too much ms it will feel weird literally like you cant think and it will scatter you wayy more in worse ways than regular meth scatter and just make you feel not right, also it will smoke too quick in the pipe thats how you know its jumped with ms or when your mixing up a shot there will be heaps of undisolved shit in the bag. Good meth should be shardy with some nice chunky rocks and some rocky shardy stuff , not weird shaped massive rocks that usually indicates jumped.
And the old speed jumping technique ive seen or heard of people jumping meth with speed to save on $$ or selling people rocky speed and telling them its meth ( its not the same thing, regular amphets can be rocks too its called smokeable gas)