I guess this gives the answer on what action to take in this situation. It appears that the tailstrike happens because people keep on pulling aft when the aircraft does not lift off.
"An Air France Boeing 777-200 freighter, registration F-GUOC performing freight flight AF-6724 from Paris Charles de Gaulle to Mexico City, was accelerating for a balanced takeoff from Charles de Gaulle Airport's runway 26R when the crew detected the aircraft was not accelerating quickly enough and firewalled the engines. The aircraft took off without further incident, while the crew discovered their takeoff weight had been programmed 100 tons below actual takeoff weight, which had caused the incorrect takeoff power and reference speed computations. The flight completed a safe landing in Mexico City about 11:15 hours later.
The airline reported: "Air France confirms that a data insertion error on take-off of cargo flight AF6724 operated by a Boeing 777 F from Paris-Charles de Gaulle to Mexico on May 22nd 2015 led to insufficient acceleration at the beginning of take-off. The crew, who noticed this slow acceleration, immediately reacted by applying full thrust. The aircraft took off normally and the flight continued to its destination. The crew spontaneously declared this event by ASR (Air Safety Report) and informed their superiors." The French BEA was informed.
On Jun 2nd 2015 the French BEA reported in their weekly bulletin that the crew used 243 tons of takeoff weight instead of 343 tons for computation of their takeoff performance, the resulting speeds were input into the flight management system. During rotation for takeoff, the crew noticed the aircraft did not become airborne, firewalled the engines, established maximum pitch possible without tail strike, lifted off, climbed out to safety, and continued to destination. "