Going to Mass is between you and God.If we read the Saints they kinda did what they wanted in certain parts of the Mass.If you feel pressured to give the sign of the peace give a wave to the people in front of you and in back of you and then kneel down.
I used to attend Mass every Sunday in Havana. When it came time to offer each other the Sign of Peace, the men would offer the revolutionary salut, with the fist held high in the air.