I’m not familiar with the term ‘slipping’. Is that the same as taking cuttings? If so, the answer is ‘yes’’, although I’ve not done it myself with petunias. So try researching using that term. Here’s one reference. You need to do soft wood cuttings. https://www.rhs.org.uk/advice/profile?pid=307

Floral, thanks so much. Yes, taking cuttings! My Mum used to do this with impatience plants. I am trying to find my rooting hormone, Can't wait - don't even know what type of petunia it is, but that will be part of the fun, Cheers. I will share pictures when they bloom. :)

I would remove the whole plant from the poinsettia pot and replant it.