If you do something lustily, you do it with a lot of strength and healthy energy. People sing lustily in church, shout lustily at a match, or eat lustily when they are really hungry. The word feels a little old-fashioned and cheerful — more like a story or a sports report than a text message. It is not about sex, even though it shares letters with lust. Picture a red-faced crowd singing at full voice, not a dirty look.

起勁地；使勁地；精力充沛地