When i masturbate it takes atleast 6 min to ejaculate. how to last longer than this during sex?

Practice: I can't tell from your question whether you want to ejaculate sooner or later. This is largely a matter of practice with your partner. For premature ejaculation, the squeeze technique is a better long-term strategy than a medication (ssri) or anesthetic. If you are not able to ejaculate, talk with your physician and if no cause is found ask whether yohimbine is a possible treatment.