How can I make the "High Five!" taunt togglable?
The following will replace your default action item H key with a toggle version. Note that this technique is a fairly standard method of making a toggle out of any +- "hold down the button" type of command.
bind H toggle_action_item
alias enable_action_item "alias toggle_action_item disable_action_item; +use_action_slot_item"
alias disable_action_item "alias toggle_action_item enable_action_item; -use_action_slot_item"
alias toggle_action_item enable_action_item
If this works and you want to keep it, put it in your autoexec.cfg.