Depends what he’s being pushy about, I normally tell them that the items will be posted the day after funds clear, which puts the onus on the buyer. If its about the money being transfered/paid etc.. then sell to the 2nd guy before you loose both sales.
A bit OT but I’m selling a Drysuit at the moment and one guy I’ve spoke to on the phone now wants me to send him £500’s worth of suit so he can try it on??? No mention of I’ll pay in full and if I decide not to take it deduct your postage cost from my refundable monies, or anything. I know there is an element of trust etc.. on both parties but come on???