Females who expect males to play differently in mixed than they do in same sex doubles matches should just not play mixed imo. That attitude is one reason why I played one season of mixed and then vowed 'never again'. In that season I had several female opponents who would stand well inside the baseline when receiving my serve then give me the stink-eye if I dared to hit a body serve at them.
When should you serve and volley in doubles? Only when you want to win.