How many kisses can you give to your boyfriend? If you're Sonic The Hedgehog that number is basically infinite. Sonic loves giving Knuckles kisses. Neither of them know how it started but it hasn't stopped since. Kisses on the forehead. Cheeks, nose, and lips. Maybe Sonic is a very affectionate person around Knuckles. It's not like Knuckles minds the kisses.
Making Knuckles like being showered in affection. Maybe it's the combination of Sonic being extra touchy feely with Knuckles and Knuckles not stopping Sonic due to him enjoying it more than he'll ever admit. Maybe it ended up being a thing that they do, no matter how it came about.
Tails likes to make fun of their romantic stuff. Ever since Tails found out about the two many jokes were made at the couple's expense. Amy does to a lesser extent. But they don't do it too often, especially when it could get annoying. They do it more on the battlefield when Knuckles and Sonic are supposed to be working yet they won't stop being affectionate.
Sonic likes giving his boyfriend kisses. It's that simple sometimes. Maybe even too simple. It's not like there's anything wrong with it. He likes being affectionate with others, especially his boyfriend. Who he enjoys way too much.
