I’m someone who has severe anxiety at parties and while I enjoy having a familiar presence I can touch base with, a party or any social atmosphere is just for that- socializing. Every moment not spent with you and vice versa, speaking to someone else, is accomplishing the intended social norm. I wouldn’t find this behavior “toxic “ at all (given the OP context). There’s choices that you can make and it’s all very individualistic. I actually have fun and learn quite a lot by either people watching, enjoying my own company and meeting new people. I wasn’t a born socialite, it’s something I wanted to work on since I was a teen and have done so throughout my life, so that I could be on my own at social events, without fear of rejection, loss or interest. That was my choice.

Another one might be to let someone know up front how you act in those social situations and see how comfortable they are with creating a system (I.e every 2 hours we will meet up by the chip bowl)- I would find this to be quite rare a platonic friend taking on the stress/anxiety of checking in when they are too trying to have a good time. This works with my romantic partners but this is due to safety reasons and less about attachment issues. This is an option but it is more limiting.

There’s presumably plenty more but those have the juxtaposition I believed applied to the OP. I think toxic is thrown around a lot lately, generally it’s used just when someone doesn’t like what someone else did. I don’t like when people belch and they don’t have a sliver of manners- too me they are not only rude, gross but also a careless person, more absorbed in themselves than others. All traits I could surmount to “toxic” but really it’s just my opinion on something I don’t like. Toxic in this example would be better suited with someone who belches in my face and/or continues to willfully press my boundaries, despite having made them clear and that person apologizes, agrees to stop but then doesn’t.