I never knew this was a real thing! I do it all the time, because I’m a silly guy, but apparently it’s something definable. It showed up on my “word of the day” list, and I thought it was really cool!
Spoonerism: the transposition of usually initial sounds in a pair of words.
“I tooked the curkey” (I cooked the turkey)
“A sacon bandwich” (A bacon sandwich)
I do this a lot, much to the annoyance of my family. I must warn you, however, if you start to automatically speak in spoonerisms, you can get into trouble. When you’re discussing Robin Hood with your 8 year old, be careful with Friar Tuck. You’ve been warned.