hot and heavy

1. 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.

2. 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.”