Personally I don't mind if either of them is top or bottom or maybe they could even switch but like
here are the scenarios
Seonyool as top; He'd be very gentle with him because he knows Yechan is still a kid at heart and Yechan as a bottom would be cute too. BUt THEN LIKE Seonyool would be like,"Am I going too fast" AND YECHAN WOULD BE LIKE,"I love you, ya know that right?" AND SEONYOOL WOULD JUST LIKE GET FLUSTERED
Yechan as top: YECHAN WOULD BE THE CUTEST TOP EVER AND LIKE SEONYOOL WOULD BE A POWER BOTTOM GUIDING YECHAN THROUGH ALL THE STEPS OF HOW TO DO IT AND WHEN SEONYOOL FINALLY SEES IT HE'S GONNA BE LIKE,"That's not going to fit" (Yechan ain't big and buff for nothing)
Personally I don't mind if either of them is top or bottom or maybe they could even switch but like
here are the scenarios
Seonyool as top;
He'd be very gentle with him because he knows Yechan is still a kid at heart and Yechan as a bottom would be cute too. BUt THEN LIKE Seonyool would be like,"Am I going too fast" AND YECHAN WOULD BE LIKE,"I love you, ya know that right?" AND SEONYOOL WOULD JUST LIKE GET FLUSTERED
Yechan as top:
YECHAN WOULD BE THE CUTEST TOP EVER AND LIKE SEONYOOL WOULD BE A POWER BOTTOM GUIDING YECHAN THROUGH ALL THE STEPS OF HOW TO DO IT AND WHEN SEONYOOL FINALLY SEES IT HE'S GONNA BE LIKE,"That's not going to fit" (Yechan ain't big and buff for nothing)