Bachelor thesis: cite my own paper? I am currently writing my bachelor thesis and since my results were really good, my advisors encouraged me to write a paper about it. The paper was accepted at an international conference and will get published and in the corresponding journal.

I've really invested much time in the paper and the results, thus my thesis fell a bit short. Additionally the topics are identical, because I wrote about the results that I achieved during my work for my thesis. Therefore it is really hard to write a "completely different" text in the thesis compared to the paper.

Moreover the deadline of my thesis ends in 3 weeks...thus, my second advisor suggested to mostly copy+paste stuff of my paper, because it is good and was reviewed several times.

However, my second advisor is always relaxed and calm. I haven't talked to my first advisor about this so far...but I suspect that he would not be too happy if I copy &amp; paste large parts.

What is the "standard" in academia for comparable situations?
Would you feel OK with copying certain parts of your paper?

Any advice would be great and really appreciated.
When it comes to copy and paste, I'd certainly have a bad feeling. Paraphrasing/rewriting is the least you can do. In general, citing own publications is common practice. Citing your own publication in your bachelor thesis is therefore, in my opinion, completely okay. 

Since the research published in your paper is actually part of your thesis, everything should be fine. But in your thesis you should be able to give even more detail than in a conference paper. That way you can reference your paper, showing that you published successfully, and then show your findings to a bigger extent.

Good luck with your thesis!

Edit: Almost forgot about your first advisor: Talk to him/her! There is no reason to feel bad for asking. Ask your second advisor for advice on how to talk to your first advisor.