Passionate, lustful, as in "They were awfully young to be so
hot and heavy about their romance" . This slangy term employs
hot in the sense of “sexually aroused,” a usage dating from about 1500.
Very enthusiastic and excited, as in "That was a
hot and heavy debate" . This slangy expression employs
hot in the sense of “characterized by intense feeling,” a usage dating from the tenth century a.d. , and heavy in the sense of “serious.”