You can do this as a discount using the item ID as the trigger.
For the trigger select "Number of Items with a Specific Column Value":
Number of items where 'ID' has a value of '1' is '>' a value of '1'
This assumes the discount is applied to item ID 1, change this to the ID you wish to use.
For the discount calculation use "Based on Multiple of Column Subtotal":
SubTotal of Column 'Quantity' 'Times' '34.99' 'Minus' '34.99'