i have a recent experience regarding this topic.
recently i noticed my newly acquired longcoat chihuahua nga sige'g sunod2x sa ako male stud, unya si kingsley pod gaceg lick sa iya vagina... but whenever i check naman pod iyaha, dili man hubag ug wala any traces of blood whatsoever...but mao lagi ang dam gacgeg paatubang sa iya rear sa ako mga male dogs.. LOL
so to settle the matter, i brought her to the vet last saturday and have her smeared..
lo and behold, she is nearing heat na gyod diay... not yet heat but near to it... few days more and she is good for stud na. its strange kay her vagina is not swollen and have no blood gyud.
btw, the smear test cost 250.00 w/o prof fee na.