If working two jobs can I pick which job I pay child support out of?

Is there an income withholding order in effect? If not, sure; the paychecks come to you and you pay child support yourself.

Both jobs were considered in figuring the child support you owe, correct?

In considering child support all forms of income are thrown into the calculation. You dont get a choice.

As I suggested earlier, both jobs are included, as well as any other income, such as income from odd jobs, annuity, pension, royalties, etc.

But as I read the question, OP wanted to know if he or she could pick which of two jobs from which CS would be deducted. As I indicated, such question only makes sense if it is deducted from her/his pay before received, as through a withholding order (or garnishment) of some sort.