NASUWT's leader said there is a "ticking time bomb" if male pupils cannot be helped with misogyny.
Staff at Tewkesbury Academy first walked out in February due to disruptive behaviour among pupils.
Teachers are walking out for 12 days in March and April over lack of action on poor pupil behaviour.
A union says schools should practise emergency responses as they do with routine fire drills.
Teachers at two Greater Manchester schools took to the picket lines after claims of violent children
Members of staff at Tewkesbury Academy could strike for nine more days.
National strike action by the EIS union over teachers' workloads could potentially close almost every school in Scotland.
Teachers at primary schools in Moston and Dukinfield say nothing is being done to improve safety.
Teachers walk out for two days at Haydon Bridge High School after talks with management stall.
