1)
What is the significance of giving his Cheil to women?
1.
Rashi: Cheil is strength. Do not weaken yourself [via excessive intimacy].
2.
Malbim: Because you are my chosen son, your strength should be for Avodas Hashem. Do not give it to women!
2)
What is the meaning of "u'Derachecha Lamchos Melachin"?
1.
Malbim: Do not let your ways and conduct erase kings from the Sefer of their lineage, that due to these matters, they are not proper for kingship.