press together
To apply pressure to two or more people or things in order for them to be sealed or stuck close together. A noun or pronoun can be used between "press" and "together." We pressed our lips together in a passionate kiss. We use steel rollers to press together the various materials. The thronging crowd pressed Janet and me together for the duration of the train ride.
press something together
to use pressure to close or unite things. He pressed his lips together and would say no more. Why are his lips pressed together so tightly?