You shouldn't ask a man how big their penis is.
Sandra has been talking to a new guy, and she likes him very much.
Sandra wants to flirt with the guy so that he knows she is sexually attracted to him.
Sandra sends some late night texts telling him how she wishes he was cuddling with her.
Sandra texts the guy asking how big his penis is, hoping to let him know that she is interested in him sexually.
The guy reciprocates his interest, and they eventually get into a relationship together.
The guy interprets her text as her only being interested in his size, and he stops talking to her altogether.