AncestryDNAKnow Your Pet DNA: Dog DNA Breed Identification Test, Genetic Traits, DNA Matches, Dog DNA Test

Q: Any tips on collecting sample. My dog won’t let me in his mouth

The dog doesn't need to open the dog's mouth to get a sample, a cheek swab is sufficient. You'll still need to swab it around for a bit. I don't think any dog likes to get swabbed, but high value treats can make the experience more pleasant for them.