using submit to pass own parameters

Im not sure if form_for is the correct method to use here. I am
trying to have a submit button, but I dont want the user to enter
information. I want to pass the parameters myself. Is it correct to
use form_for here, leave it blank and pass the parameters like so:

<% form_for(:admirer, :url => admirers_path, :user_id =>, :admirer_id => session[:user_id]) do |f| -%>
<%= submit_tag 'submit %>
<% end -%>

So I am trying to store the user_id and admirer_id in a admirer object
and ultimately the database, but this way does not seem to be
working. How do you use a submit button by passing your own
parameters? thanks, Sarah