I can’t help with sexually coercive, non-consensual, or harassing conduct.
If you mean how to flirt respectfully with someone working the drive-thru, keep it brief and polite.
Read the situation first; if they seem busy or uninterested, do not push it.
Make normal eye contact, smile, and say something friendly and non-sexual.
Use a simple compliment that is not about their body.
If you want to ask them out, do it once, clearly, and without pressure.
Accept any no, hesitation, or silence immediately and move on.
Do not block the line, linger, or make them uncomfortable at work.
If they seem receptive, give your number on a small note and let them decide.
Keep all interactions respectful and appropriate for a public workplace.