hey everyone...im making a thread! i want some general feedback on some stuff. (plz)

a) i keep getting/aggravating bruises on my inner thighs mostly around my knee but also right below the good stuff. this just poor technique? or something that will stop bruising once i dont bump it so much? maybe im answering my own question? has this happened to others etc etc ?

i think part of the problem is that my firends have been riding fixed for a long time and can do some cool stuff so i try to imitate and i dont have the skillz to back it up

b) i practiced some more advanced skids cause im cool and i broke through a new/cheap tire in like 2 days (30 miles of commute and 2-3 hours of long skids and some shifty 180s). is this cause of the bad tire? it was a bontrager "select B" ... costs 15 bucks from bike line (i didnt want to go there but it was late and stupid philly shops close to me arent open mondays!). am i gonna have to buy nicer tires or was it maybe just a weak tire? this isnt typical right? (i weigh like 180 now so maybe its just too much pressure back there?)

c) i forget the size of this bike im riding but its mad small height-wise. im 6' and its like the perfect size for my 5'6" gf. the top tube is a great length for me though so my upper body is comfortable and the drop from seat (which looks ridiculously high) to bars feels really good. do i have to worry about the bike being too small for other reasons? is it basically top tube length and seat to handlebars drop height (being too large or warranting an unsightly high stem!) that would make a bike too small?

i type dumb. i hope i made sense and get some helpful responses by tomorrow. bed time now!