Yep, it happens all the time, every day in many different situations. Straight men and women and gay and bi men and women. Straight men appreciate a good bulge even though they don't want to suck one.. They look all the time, it's natural. I notice people looking at me sometimes too.
I went in a bank recently and talked to a male staff member. I easily noticed he looked me up and down. Later in the conversation I looked to the side momentarily, but my peripheral vision noticed his eyes dropped straight to my lower torso immediately. Not sure if he looked at my dick, waist, or what, but I noticed a very immediate, intent looking stare down below.
Everybody loves a bulge, straight or gay. Thing is there are just as many bi and gay men and women as straight, out there every day checking out dick bulges, nice tits and asses.