Stick a plastic tube up yer butt and bubble away.
You might want to use a trap or check valve, beecause toulene up yer ass is no fun, trust me.
This is what's been done,all jokes aside, titurate the freebase solution (with hydrochloric acid)and azetropically distill off the water as a toulene azetrope, watch crystals appear. works just almost as well as gassing, but SWIS likes to gas , SWIS uses a coke bottle, drill two holes in the cap, fill with salt and HCl wrap teflon tape around the threads, place cap, use rubber as a 'gasket' for your tubing, fill a basting syringe with sulfuric acid, and drip onto the Hcl salt paste, gas away.
This thread should be in the newbee forum.