What is the meaning of "Dalyu Shokayim mi'Pise'ach"?
Rashi: They were elevated. This is like "Dalu Einai" (Yeshayah 38:14). Other people's thighs appear to a lame person to be higher than himself.
Malbim: The verse depicts that the Chamas that he drank cut off his legs and made him lame due inebriety, it sends words to the lame to lift his thighs/ The thigh is above the leg, and stands up the body. The thighs support the body, and the thighs are on the legs. However, a lame person who cannot walk with his legs, his thighs are a burden. He needs to lift and cut off the extra (useless) thighs.
What Mashal do Kesilim say?
Rashi: They say this Mashal about learning Chachmah. How do we come to learn Chachmah elevated above us?!
Malbim: A Kesil is drunk with wine of desire, and he cannot stand in his legs, i.e. he cannot conduct according to the ways of Chachmah, for he staggers like a drunkard due to his desire. He wants to cut off the thighs - the foundations of Chachmah, via casting doubts in it. Since he is lame due to his desire - he does not stand against it, the thighs on which man stands (the laws of Chachmah) are useless and a burden to him.