Im uncircumsized and worried about sex.?

Ok my other fears are gone and done, Past. They were about if girls liked or hated the foreskin and every girl i have told said i like it or its alright i dont care. so heres the new thing. When i have an erection the skin doesnt pull back just a little bit of the tip shows. so im scared what should i do to stretch it out? or do i need to do. i have 2 girls wanting to do tuff with me and its upcoming. SO LONG STORY SHORT WHEN I GET AN ERECTION WILL IT RIP INSIDE A VAGINA AND IF SO HOW SO I PROCEED WITH IT? THNAKS GQK