An electrical connector assembly includes a plug body comprising a first housing part and a second housing part with a plug-in portion. The housing parts are movable relative to each other along a housing axis. An elastic element holds the housing parts against each other. The second housing part has a projection with a first sliding surface diagonally to the housing axis. The electrical connector assembly further includes a mating connector having a collar with a second sliding surface cooperating with the first sliding surface. The second housing part is displaced away from the first housing part along the housing axis against a restoring force of the elastic element. The second sliding surface ends at a recess in the collar, so that the elastic element pulls the projection into the recess and locks the plug body with the mating connector.