Why my girl have her heat again? She had her heat 2month ago and start to have it again...

I took an appointement at the vet but she have no problem at all, she only have her pheromones. Male wanna climb her and other dogs smell a lot her genitals. And she "fuck" some cushion lol (this is what she do when she have her heat). No blood yet, no pain, she is feeling good and happy as always. Sha have those symptome for about a week. It has calm down a bit, she just "fuck" the cushion one time a day

I know human hormonal gel can cause heat but I don't use that. I also see that a male particularly horny can "cause" heat, is that true?

Thank you very much btw, I don't want to sterilise her for a lot of reason (and having puppy is not one of the many reason, please don't try to argue about that, thanks)