The correct spelling of the phrase "hast sexual intercourse" is "have sexual intercourse". The word "hast" is an archaic form of the verb "have" that is no longer in common use. The IPA phonetic transcription for "have" is /hæv/, while "sexual" is pronounced /ˈsɛkʃuəl/ and "intercourse" is pronounced /ˈɪntərˌkɔrs/. The correct spelling of words is important for clear communication, so using outdated or incorrect terms can lead to confusion and misunderstandings.