Groping,slut clothes,sharing gf

okay,my gf is 20 pettite and loves to be gangbanged or to take a lot of cocks in all her holes,we never done something like that but we want to,we was thinking to start slowly first by dressing her like a slut and go in public(short skirt with no panties,candid,shorts with ass cheeks out and stuff like that) so we gonna start like that and if we like it we will let someone to grab her ass or finger her,if we like it we gonna go for more like letting her to blowjob him,she also want big black cocks(yes her ass is little but can tale huge things).
So any ideas are welcome and other couples,or bbcs pm us