Most guys who have to do both at the same time just sit to do both. It's quicker and easier.
My hubby - who is cis - always uses the stalls when out in public, even for a no. 1, because he doesn't like whipping it out in front of strangers. Can't say I blame him. He'll stand in the stall if it's just a no. 1, but he'll sit if he suspects he needs to do both. At home, he sits pretty much all the time, even for just a no. 1.
Men generally seem to be allergic to each other in public toilets so nobody's going to care what you're doing or what position you're in whilst you do it. It would be a major faux pas if anyone were to question you on your toilet habits. The goal of men's toilets is to get in, get your business done and get out as soon as possible.
BTW, back when I was a teenager and I was all militant about standing to use the toilet, I used to do no. 2s from a standing position. True story. Don't try this at home, kids!