I would tell them they’re absolutely right and that you totally misread the tone. I’d say I genuinely DONT have a foot thing and would have dropped it immediately if I had accurately assessed that tone. I’d say I understand if they don’t want to talk to me again, but that my friends are important to me and I’d hate to lose one of few over a bad joke. I’d tell them I guess I didn’t know them like that well enough to push those buttons and would definitely not have had I realized the actual situation. Basically I’d just stress I misread my audience and went down the full joke path. If they seemed open to discussing it or considered your apology, I might add that after the fact I remembered the ridiculous posts about feet I had made some time ago and facepalmed when I realized how that must have looked in retrospect. The ball is ultimately in their court, best you can do is be honest, but this will leave you vulnerable. The way I’d look at it, is I’d rather just put everything on the table and not wonder what I could have done to save it later.