here is a good way to do it:
It could be like a PS as in the other person will have to use his/her Ki to strugle loose, and if they loose the stugle they are sucked up and die and Cell's power level goes up like 1/4 the enemy he absorbeds power level. also it could be a pinpoint attack as in he has to be right in front of them and he has to be dead on plus it could have a rate of fire like the freeza disk so he cant just go constantly. Also the more powerful he is the faster he can "shoot" his tail at the enemy. So I think that is a great way of doing the cell absorb attack
also they are putting the Buu Wrap attack in the next version of ESF or the version after that