assuming the female in question is interested and consenting, yes, it is ok to have sex with them. lube is a good idea when they're in heat, too.

also, it's not monthly for dogs... it's (usually) every 6 months.

[edit: added the last line.]

Well, first and foremost that should be left up to her....if she's receptive she will allow it out of heat. Lube may or may not be needed depending on how attentive you are to her

the rest of the month

Dogs typically go into season twice a year, though some lineages will have 3 seasons. Please, educate yourself on the biology and behavior of dogs before attempting anything.

I am not experienced on this matter, but I'll do my best to relate what I've heard.

First, I've heard that, at far as "fitting" goes, it is actually somewhat easier to fit when the dog is out of heat than when they are in heat, because in heat there tends to be some swelling of the genitalia. However, outside of heat the dog might be more tense, which can counteract the above effect if care is not taken to ease the dog into such activities more than usual. This all might be complicated by other details, such as the dog's age, breed, and general size.

Plenty of lube is generally a good idea regardless of whether the dog is in heat or not.

A big question about this sort of thing is whether or not the dog would want sexual contact out of heat, and that is what I've heard the most mixed responses on. I've heard from some that dogs really shouldn't be engaged out of heat, because whether or not they'll accept such advances, it's less clear, because during heat is when they are the most into the activities, and consent the most clearly. On the flip side, I've heard of some people who won't have sex during their dog's heat, because they feel that's when the dog isn't really in control - she's at the whim of her incredibly demanding body, and as a result her consent cannot be taken as valid. I feel as though most people tend to fall between those two ends, and argue that any time can work as long as you make sure the dog is happy with the activity.

One thing I have heard consistently is that if you are going to have sex outside of heat, you should take things slow, both that you make sure to clue into the dog's wishes particularly well, and that you don't do anything so quickly that their body is not entirely ready for it, and it ends up hurting them.

I don't know your particular circumstances, but I can say that "making love" also doesn't necessarily require penile-vaginal intercourse. If size is a problem, for whatever reason, but you still want to be sexual, it might be worth considering the possibility of cunnilingus, for instance?

I don't know. Don't take anything I'm saying too seriously I guess, because of my inexperience, but I wanted to try to sum up the debate and information I've heard on this subject as best I could.

I have quite some experience in this matter. And the answer to your question is...it depends.

Each dog is different. Their attitudes about sex and their sex drives are all different.

That being said, MOST will be during heat only. At other times they will be too small for penetration and definitely not interested in you messing around back there.

Once they come into heat their vulva will expand and swell and the sudden rush of hormones will make them a lot more interested in sex. Some can become instant nymphos.

Heat generally lasts approximately 20 days and comes twice a year usually about 7 to 8 months apart. This varies a lot from dog to dog.

And lube is always necesaary...whether in heat or not. Plain unscented water based lubes ONLY.

I'm only into male dogs :/ so can't help here

I feel it's worth mentioning that female dogs are usually very clear about what they like and what they don't, even with their owners. Just read her body language, see whether she's enthusiastic about what you're doing, so on and so forth.

Females have to be clear enough to communicate with some very stubborn male dogs, so it shouldn't be difficult for you to see when she wants it and when she doesn't.