The best is to let her wear her panties or tanga and then stand behind her with your cock between her thighs. Then with her thighs gripping your cock, you fuck her with the fabric of the panties/tanga rubbing your cock. It is delicious. If you stand her in front of a mirror you can both see your cock ejaculate all your spunk and see the dribbles of spunk drop down her thighs.
Love to be wearing a short skirt and feel a hand under it and then feel a cock cum inside my panties and feeling it running out into my panties and down my legs makes me feel very feminine and sexy