neutered chihuahua tying with un-spayed

Question
hi.
i have a 7+ year old male chihuahua that i had neutered very early in his life.  knowing that chihuahuas crave the company of other chihuahuas, i recently acquired a beautiful little female who is now 8 months old (due to the untimely death of his older "brother").  at this time i am choosing not to spay her, as i am seriously considering mating her in a year or so.
she is currently in her very first season.  at first it didn't seem to pose much of a problem.  i bought her a washable puppy diaper but eventually (after a week & a half or so) became lax in enforcing her to wear it.  all of a sudden - within the last week - my male chihuahua & her are attempting to go at it "like bunnies".  she usually initiates, but once she gets him riled up then they are equally aggressive to one another.  i didn't worry much at first because he could never find THE spot anyway - & would often wind up humping her elbow or the side of her head or wherever else he managed to land.  but he has now learned where to stick it!  obviously, i do my best to prevent this behavior, even though i know its inherent.  but as a "single mom", i can't always stop nature from occurring.  ...two times this past week when i've removed her diaper so that she may go potty they have gotten tied together.  then she gets out from underneath him & they wind up butt to butt, with his poor lil' penis bent all the way under her.   
i have heard that it can be very damaging to separate them, but it also appears to be very painful for him.  perhaps i am reading too much into it, i don't know.  but he is a very special dog with a lot of anxieties & i really feel he does not like this butt to butt thing.  she tried to run the other day in that position & just drug his poor lil body across the pavement behind her.
i don't know if i should splash them with water or allow them to release on their own.  the first time this happened i did put them in the tub (THAT was awkward) & turn on the water & it worked.  this last time i began freaking out because i couldn't get the hose on & eventually just clapped & raised my voice at them until they finally separated.
i'm sorry, this is all so new to me.  i hope i've made sense & not rambled on too much.  i really just want to know how to handle them tying in the event that it should occur.  as i mentioned, i am a "single mom", & separating them during her season is simply not an option.
thank you so much for your help.

Answer
Hi Michelle. First, I have to ask, when you had your boy neutered, were both testicles dropped? Is there any way that he had a retained testicle? If they tie, don't seperate them. You can cause more damage doing that. The butt-to-butt position is the normal position that dogs take when they tie. This goes back to their wild days. They took this position in the wild so they could both watch for predators. Make sure you hold them in place until they come undone, so neither one gets hurt. If the female takes off, and drags him, she can cause some serious damage to both of them. The best thing to do when two dogs are tied, is to keep them calm, and hold them until it's over. If the male really doesn't like the butt-to-butt position, then you could try to hold him in place on top of her until they come apart. Good luck, and if there's anything else I can help with, let me know!