There is a picture on the Woodhaven Labs website - GREAT website!
There are two glands on the penis, near the base. These glands swell up when the dog gets sexually aroused. The glands allow the penis to stay inside the female - creating the 'tie'.
Trying to pull apart tied dogs could be VERY harmful to both. Unless they are fighting you just have to let nature takes it course.
When breeding dogs most people will stay with the pair - making sure that neither dog tries to struggle. When I bred Kaynya she was fidgety at the beginning of the tie so I had to hold onto her to keep her from moving and hurting either herself or the male.
Once the male is in and tied he will move off of the female, flip his leg over her back and they stand butt to butt. Everyone says this is a more comfortable position for the dogs during the tie. While I can agree that the female may be more comfortable (not having the male hanging on her back anymore) I just can't see how it's comfortable for the male to have his penis bent backwards! Ouch!!
Once the penis is inside the female she CAN get pregnant. They do not need to 'tie'. Sometimes the male does not swell and so doesn't stay inside the female for long. This is referred to as an 'outside tie'.
Females CAN still get pregnant with an outside tie.
I found this info while Googling - I don't know how valid it is:
Quote:The ejaculate of a dog is passed in three fractions. The first fraction of clear fluid is virtually sperm free. The second fraction is richest in sperm, and is released immediately after thrusting. The third fraction is a larger quantity of prostatic fluid containing some sperm, and this is delivered as an intermittent ‘drip feed` which helps transport the sperm to the oviduct.
Some ties can last just a few minutes (inside or out) and some can last a looooong time!!
My first experience breeding was back when I had Neke. My breeders husband and I were in their basement with Neke and their stud, Ozzie. We got the breeding and they tied. It took 45 minutes!!
You don't want it to last TOO long as it can become uncomfortable for both dogs. Bags of frozen veggies (peas work best) can be applied to the underside of the males penis to help reduce swelling.
Spraying them with water will do nothing other than aggitate them and possibly cause injury.