No, the sensor must be removed before intercourse. You do not necessarily have to put it in its box, as trackle notices when there is an interruption in the measurement. However, if the interruption lasts longer than 1 hour, you should put it in its box in the meantime.
After the intercourse you can reinsert your sensor as usual. Please note that trackle should be worn for at least 4 hours at a time to record basal body temperature.
PS: The trackle sensor is only used to determine the fertile and infertile days and measures your core body temperature while you sleep.
If you do not want to get pregnant, you must use a contraceptive method of your choice on the fertile days (e.g. condom) or abstain from vaginal intercourse.