In the heimlich maneuver fist is pressed into abdomen with what?

In performing the Heimlich maneuver, the correct term is "fist", not "first". The person performing the maneuver creates a fist with one hand, and places their other hand over their fist. They then forcibly push upward and inward into the abdomen of the person who is choking, in order to help expel the obstructing object from the airway.