You never know what male just bred a bitch in the last few days either...her scent is going to be all over his rear, so when he sits, voila, bitch in heat smell on the ground. Our males have to behave like "normal" with bitches in heat. If a bitch is in, they're run first. The males not allowed to put nose to the ground, they get reminded with various "hearing aids" if they do. I've had a bitch in heat a month going on the third month now (three different bitches). I bring my bitches in heat inside and crate them (we don't have a separate bitch pen "yet"). Right now, I have my two young males (ages one and two) and our neutered late in life male inside as well. The two young males are crated as well unless directly supervised. To go out to air, they must go by where the bitches in heat are crated. They're not allowed to stop and "talk" to the ladies in heat, they must go outside as "normal" routine. The two year old hesitated for a second this morning, any more than that is not tolerated, he will be verbally reprimanded if he stops again until she's out of heat.
Hickory, our yellow male we lost several years ago would not mount a bitch that didn't have KY jelly applied. She could be flirting, tossing the tail, backing up to him, you could even hold her and encourage him, but he would NOT do it without the KY. Watched him turn his nose up and would bump her, but wouldn't mount. KY applied and he proceeded without a second thought. He was bred that way in the past, so he wouldn't do it without. (NOT saying if left totally unattended it wouldn't eventually happen, but we only breed with supervision to avoid injury.)