Update # 2.
I am now in Monterrey for work, 3rd largest city in the north of Mexico.
Many hot guys on Grindr and Scruff, definitely in general better looking here than in Mexico City.
I found so far (in between some nice free encounters..) 2 masseurs.
I paid 40$ for each of the two massages. The first (hot guy, muscular, in his early 30s, super hung) was just a rub, quite mediocre, but 15 minutes into massage all of the sudden it became a hot sex session, and I had to accept his insisting request to top me
The second was another hot muscular guy in his 40s who came to my hotel, gave me an amazing naked massage on a table, and we ended up having lots of mutual oral enjoyable fun.
So far, I like Monterrey!