There's a category for this in the extensions:

https://www.speedrun.com/portal_2_category_extensions#No_Major_Glitches

Basically, you're allowed to do tricks like bunnyhopping, but major things like funnel flying are out.

i sometimes do

There's a no major glitches segmented run in the works by the community right now, as well as a no major glitches coop all main courses run that will sort of begin that category extension.