So,I bumped my buy thread a while ago. And i wanted to edit my first post so i pressed quote instead of edit without me noticing. After i posted the supposed "first post", it merged with my bump. So i deleted the bump. The thread returned to the place it was before the bump, and not on the first page of Items subforum. Before i deleted it it was on the 5th place of the lists of threads with new post. So i bumped it once again and it went back on the top of the 1st page. So here's what im saying:
If you bump a thread and delete the bump, the thread should stay where it is during the bump, and not go back to the place/page it was before. If a guy bumps a thread without anyone noticing they would just delete the bump and do it once more. That is cheating

If I'm interpreting what you're saying correctly - If you bump your thread earlier, delete that bump, and then re-bump later, it re-appears at the top? Then yes that is cheating.
Lucky for us, that's already against the rules, and can get you infracted.

Yep

but it should be:after you delete the bump the thread should stay where it is. And if you do delete the bump and bump Again, it shoudnt go to the top, to cause the Toristaff less trouble

When you delete a post, you delete it. Ergo treating the thread if it was never bumped.

Just bump it and leave it, if you accidentally press quote, just go back and try again.