Assuming you actually do get the bad guy started into the throw, if he can reach you then a common reflex is for him to hang on for dear life on the way over, and the more severe the throw, the more powerful the grab. This makes sense to him since he thinks you will hold him up. Physics does not agree usually and both parties will end up on the floor. Fortunately, we know from training that this is not usually such a good counter to a throw, since if the thrower is fairly savvy, he can use this as an opportunity to badly slam the receiver.

Of course, your best bet is to all together avoid having him muckle onto you. You should either foul his arms so he cannot grab you or be in a location where he cannot reach you for a grab, such as being behind him. E.g., doing a shoulder throw while either crossing the other arm across uke's body (juji seoi nage), throwing to the uke's rear (ushiro seoi nage). As a further example, a major hip throw can simply pin the free arm to uke's side.

In the case that he does get hold of you, you should practice throws as sutemi as well by either dropping to one knee or falling on the receiver. This requires a bit more illumination, so here is a small discussion of sutemi and its uses. Generally there are three ways you might need to go to the floor when throwing.

• You are off-balance initially. Such as off a tackle where you counter-throw. Attempting to stabilize will simply give him the throw/takedown and might well injure you in the process (can you really clean and jerk him standing on one leg? You must be very strong indeed...)
  
• You lose balance in the middle of the throw, usually from being regrabbed or due to unforseen circumstances (e.g. you are close to an object, such as a table, and the receiver grabs or snags it as you throw him, knocking you both over).
  
• You have yielded to an attack from a much larger individual whose mass you cannot support
  

In the second case, the receiver cannot tap, it should be noted, if he is truly hanging on to you and this will make the impact quite severe even on mats. It is best to have ample practice of nage komi (controlling -- well, powering actually -- the person to the ground) when he hangs on to you, but this requires thick mats and usually has an enormous amount of wear and tear on the receiver. In practice remember that when the receiver has both arms unavailable for tapping (he's hanging on for dear life), the landings can be much stouter so either extra mats are indicated or a lighter touch. There it is imperative the uke use his feet to tap powerfully.

• You are not setting the throw up properly, so they may rest assured theat there will be no elbows to the head, head twists or any other standard fare for us.
  
• You are trying to maintain safety for them, therefore you aren't blasting them head over heels, just picking them up and putting them down.
  
• You're interested in letting them understand a martial art better, rather than showing off. Treat it seriously so they will understand it is serious.
  
• Let them know you are trying to keep it safe for them and if they decide to screw it up, they will be on their own. Make good on this claim in that if you perceive a serious attempt to take advantage of your good will you are not to be suckered into something. Being critically injured by someone you are trying to "save" who is utterly clueless about the situation they have put you in is a case to be avoided. They are to be your crash pad in such cases and you are to keep yourself safe. After all they have demonstrated that they have no interest in your safety, so you must take charge of it. Admittedly they probably don't realize what is coming next, but you have warned them and while it is to be regretted, it is not your issue. Did I say you were to choose who you demonstrate this on carefully?

You should also realize that when people ask you to show them your stuff, what they sometimes really want is to show their stuff, with you in the role of really nice chump (someone to be taken advantage of). Some people have an almost pathological need to win, and no matter how civil you are, they will still try to do something goofy. Indeed, the more civil you are the more it encourages them since they confuse being reasonable with being weak. This is especially true for someone used to macho struttings -- part and parcel of "psyching out" the opponent. They tend to think they've won if you aren't making right the pre-game noises at them, plus they get lulled into the mindset that it will prove how tough they are at the same time they heavily rely on you to play by the rules. We call this cheating normally, but a romanticized "outlaw" mindset means that getting away with it no matter how stupid holds a lot of appeal for them. They can finally be a winner in their little miserable lives. (Sorry, I've run into some complete jerks.)

You'd also be amazed at the number of tough types who will tell you the being thrown is simply not effective. This is because they don't know how to throw and the closest thing they can relate it to is slipping and falling, which while uncomfortable is hardly serious. As such their courage is wide but not deep and actually seriously doing a technique on them is apt to make them frantic in which case they will up the ante and a simple demo can spiral out of control. It is best to avoid demonstrating on people like that since you might find yourself in a self-defense situation.