My (F19) boyfriend (M20) of three months won’t stop flirting with the plush i bought him, how should I tell him this creeps me out?

So we went to target yesterday and I was sick of sleeping on a squishmallow less bed at my boyfriends apartment so i bought him (me) a capybara squishmallow! It seemed like a match made in heaven as he LOVES capybaras. The only problem is we established this plush is our child and now he’s making weird sexual remarks about it. stating he “got our daughter pregnant” while I was at work. I understand this might be a bit but it’s genuinely concerning and I don’t know where the bit stops. (I also now have to buy ANOTHER squishmallow for me at his apartment because he likes this one quite a lot and my hopes of having a soft squishy pillow at all times at his house have been crushed). Please give me advice as I love him but these remarks are slightly concerning. Should I be worried? how should I approach this situation?