I can understand wanting to be comfortable with something so you don't feel like you're risking ruining your strop and/or razor. But I don't really think there is an alternative to practicing stropping your razor with your strop and razor.

You want to use a razor, because a razor doesn't handle like anything else. And you want to use a shave ready razor so you will know if something you are doing is damaging a shave ready edge. Let's say you use a cheap, dull, "razor shaped object;" you might become very comfortable with what you are doing, but what you are doing could be ruinous to the edge of an actual razor and you wouldn't know will you ruined your actual shave ready razor. Then you'd have bad habits to break.

As for the strop, I don't think worrying about cutting or scratching it makes much sense. The things that will cut or scratch a strop are pretty obvious, and if you pay attention and take your time, you won't make a stroke on the strop where you are leading with your edge or putting the edge into the surface of the strop.